WorldWideScience

Sample records for high-brightness accelerator free-electron

  1. A high brightness electron beam for Free Electron Lasers

    NARCIS (Netherlands)

    Oerle, van Bartholomeus Mathias

    1997-01-01

    In a free electron laser, coherent radiation is generated by letting an electron beam propagate through an alternating magnetic field. The magnetic field is created by a linear array of magnets, which is called an undulator or a wiggler. The wavelength of the laser radiation depends on the amplitude

  2. High-brightness rf linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.

    1986-01-01

    The issue of high brightness and its ramifications in linacs driven by radio-frequency fields is discussed. A history of the RF linacs is reviewed briefly. Some current applications are then examined that are driving progress in RF linacs. The physics affecting the brightness of RF linacs is then discussed, followed by the economic feasibility of higher brightness machines. (LEW)

  3. High-brightness rf linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.

    1986-01-01

    The issue of high brightness and its ramifications in linacs driven by radio-frequency fields is discussed. A history of the RF linacs is reviewed briefly. Some current applications are then examined that are driving progress in RF linacs. The physics affecting the brightness of RF linacs is then discussed, followed by the economic feasibility of higher brightness machines. (LEW)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-06-01

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

  5. Development of superconducting acceleration cavity technology for free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Min; Lee, Byung Cheol; Kim, Sun Kook; Jeong, Young Uk; Cho, Sung Oh

    2000-10-01

    As a result of the cooperative research between the KAERI and Peking University, the key technologies of superconducting acceleration cavity and photoelectron gun have been developed for the application to high power free electron lasers. A 1.5-GHz, 1-cell superconducting RF cavity has been designed and fabricated by using pure Nb sheets. The unloaded Q values of the fabricated superconducting cavity has been measured to be 2x10{sup 9} at 2.5K, and 8x10{sup 9} at 1.8K. The maximum acceleration gradient achieved was 12 MeV/m at 2.5K, and 20MV/m at 1.8 K. A cryostat for the 1-cell superconducting cavity has been designed. As a source of electron beam, a DC photocathode electron gun has been designed and fabricated, which is composed of a photocathode evaporation chamber and a 100-keV acceleration chamber. The efficiency of the Cs2Te photocathode is 3% nominally at room temperature, 10% at 290 deg C. The superconducting photoelectron gun system developed has been estimated to be a good source of high-brightness electron beam for high-power free electron lasers.

  6. High-brightness X-ray free-electron laser with an optical undulator by pulse shaping.

    Science.gov (United States)

    Chang, Chao; Liang, Jinyang; Hei, Dongwei; Becker, Michael F; Tang, Kelei; Feng, Yiping; Yakimenko, Vitaly; Pellegrini, Claudio; Wu, Juhao

    2013-12-30

    A normal-incident flattop laser with a tapered end is proposed as an optical undulator to achieve a high-gain and high-brightness X-ray free electron laser (FEL). The synchronic interaction of an electron bunch with the normal incident laser is realized by tilting the laser pulse front. The intensity of the flattop laser is kept constant during the interaction time of the electron bunch and the laser along the focal plane of a cylindrical lens. Optical shaping to generate the desired flattop pulse with a tapered end from an original Gaussian pulse distribution is designed and simulated. The flattop laser with a tapered end can enhance the X-ray FEL beyond the exponential growth saturation power by one order to reach 1 Gigawatt as compared to that without a tapered end. The peak brightness can reach 1030 photons/mm2/mrad2/s/0.1% bandwidth, more than 10 orders brighter than the conventional incoherent Thompson Scattering X-ray source.

  7. Los Alamos High-Brightness Accelerator FEL (HIBAF) facility

    Energy Technology Data Exchange (ETDEWEB)

    Cornelius, W.D.; Bender, S.; Meier, K.; Thode, L.E.; Watson, J.M.

    1989-01-01

    The 10-/mu/m Los Alamos free-electron laser (FEL) facility is being upgraded. The conventional electron gun and bunchers have been replaced with a much more compact 6-MeV photoinjector accelerator. By adding existing parts from previous experiments, the primary beam energy will be doubled to 40 MeV. With the existing 1-m wiggler (/lambda//sub w/ = 2.7 cm) and resonator, the facility can produce photons with wavelengths from 3 to 100 /mu/m when lasing on the fundamental mode and produce photons in the visible spectrum with short-period wigglers or harmonic operation. After installation of a 150/degree/ bend, a second wiggler will be added as an amplifier. The installation of laser transport tubes between the accelerator vault and an upstairs laboratory will provide experimenters with a radiation-free environment for experiments. Although the initial experimental program of the upgraded facility will be to test the single accelerator-master oscillator/power amplifier configuration, some portion of the operational time of the facility can be dedicated to user experiments. 13 refs., 5 figs., 6 tabs.

  8. A microtron accelerator for a free electron laser

    NARCIS (Netherlands)

    Botman, J.I.M.; Delhez, J.L.; Webers, G.A.; Hagedoorn, H.L.; Kleeven, W.J.G.M.; Timmermans, J.C.M.; Ernst, G.J.; Verschuur, J.W.J.; Witteman, W.J.; Haselhoff, E.H.

    1991-01-01

    A racetrack microtron as a source for a free electron laser is being constructed. It will accelerate electrons up to 25 MeV to provide 10 ¿m radiation in a hybrid undulator with a periodicity distance of 25 mm. The aim is to accelerate 100 A bunches of 30 ps pulse length at 81.25 MHz. This frequency

  9. Generating coherent soft x-ray pulses in the water window with a high-brightness seeded free-electron laser

    CERN Document Server

    Zhou, Kaishang; Deng, Haixiao; Wang, Dong

    2016-01-01

    We propose a new scheme to generate high-brightness and temporal coherent soft x-ray radiation in a seeded free-electron laser. The proposed scheme is based the coherent harmonic generation (CHG) and superradiant principles. A CHG scheme is first used to generate coherent signal at ultra-high harmonics of the seed. This coherent signal is then amplified by a series of chicane-undulator modules via the fresh bunch and superradiant processes in the following radiator. Using a representative of realistic set of parameters, three-dimensional simulations have been carried out and the simulations results demonstrated that 10 GW-level ultra-short coherent radiation pulses in the water window can be achieved by using the proposed technique.

  10. Generating high-brightness and coherent soft x-ray pulses in the water window with a seeded free-electron laser

    Directory of Open Access Journals (Sweden)

    Kaishang Zhou

    2017-01-01

    Full Text Available We propose a new scheme to generate high-brightness and temporal coherent soft x-ray radiation in a seeded free-electron laser. The proposed scheme is based on the coherent harmonic generation (CHG and superradiant principles. A CHG scheme is first used to generate a coherent signal at ultrahigh harmonics of the seed. This coherent signal is then amplified by a series of chicane-undulator modules via the fresh bunch and superradiant processes in the following radiator. Using a representative of a realistic set of parameters, three-dimensional simulations have been carried out and the simulations results demonstrated that 10 GW-level ultrashort (∼20  fs coherent radiation pulses in the water window can be achieved by using a 1.6 GeV electron beam based on the proposed technique.

  11. Transform-Limited X-Ray Pulse Generation from a High Brightness Self-Amplified Spontaneous Emission Free-Electron Laser

    CERN Document Server

    McNeil, B W J; Dunning, D J

    2012-01-01

    A method to achieve High-Brightness Self-Amplified Spontaneous Emission (HB-SASE) in the Free Electron Laser (FEL) is described. The method uses repeated non-equal electron beam delays to de-localise the collective FEL interaction and break the radiation coherence length dependence on the FEL cooperation length. The method requires no external seeding or photon optics and so is applicable at any wavelength or repetition rate. It is demonstrated using linear theory and numerical simulations that the radiation coherence length can be increased by approximately two orders of magnitude over SASE with a corresponding increase in spectral brightness. Examples are shown of HB-SASE generating transform-limited FEL pulses in the soft X-ray and near transform-limited pulses in the hard X-ray. Such pulses may greatly benefit existing applications and may also open up new areas of scientific research.

  12. Inverse free electron laser accelerator for advanced light sources

    Directory of Open Access Journals (Sweden)

    J. P. Duris

    2012-06-01

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

  13. Chirped pulse inverse free-electron laser vacuum accelerator

    Science.gov (United States)

    Hartemann, Frederic V.; Baldis, Hector A.; Landahl, Eric C.

    2002-01-01

    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.

  14. High brightness 50 MeV Cyclotron for Accelerator-Driven Subcritical Fission

    Science.gov (United States)

    Assadi, Saeed; Badgley, Karie; Mann, Thomas; McIntyre, Peter; Pogue, Nathaniel; Sattarov, Akhdiyor

    2011-10-01

    The Accelerator Research Lab at Texas A&M University is developing new accelerator technology for a high-brightness, high-current cyclotron with capabilities that will be beneficial for applications to accelerator-driven subcritical fission, medical isotope production, and proton therapy. As a first embodiment of the technology, we are developing a detailed design for TAMU-50, a 50 MeV, 5 mA proton cyclotron with high beam brightness. In this presentation we present devices and beamline components for injection, extraction, controls and diagnostics. We emphasize the system integration and implementation of TAMU-50 for production of medical radioisotopes.

  15. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Roser, T.

    1997-11-01

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs.

  16. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Roser, T.

    1997-11-01

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs.

  17. Conceptual design of industrial free electron laser using superconducting accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths ({lambda} = 0.3...20 {mu}m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.

  18. Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Blomberg, Ben [NICADD, DeKalb; Mihalcea, Daniel [NICADD, DeKalb; Panuganti, Harsha [NICADD, DeKalb; Piot, Philippe [Fermilab; Brau, Charles [Vanderbilt U.; Choi, Bo [Vanderbilt U.; Gabella, William [Vanderbilt U.; Ivanov, Borislav [Vanderbilt U.; Mendenhall, Marcus [Vanderbilt U.; Lynn, Christopher [Swarthmore Coll.; Sen, Tanaji [Fermilab; Wagner, Wolfgang [Forschungszentrum Dresden Rossendorf

    2014-07-01

    In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.

  19. Advanced high brightness ion rf accelerator applications in the nuclear energy

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, R.A.

    1991-01-01

    The capability of modern rf linear accelerators to provide intense high quality beams of protons, deuterons, or heavier ions is opening new possibilities for transmuting existing nuclear wastes, for generating electricity from readily available fuels with minimal residual wastes, for building intense neutron sources for materials research, for inertial confinement fusion using heavy ions, and for other new applications. These are briefly described, couched in a perspective of the advances in the understanding of the high brightness beams that has enabled these new programs. 32 refs., 2 figs.

  20. A high brightness proton injector for the Tandetron accelerator at Jožef Stefan Institute

    Energy Technology Data Exchange (ETDEWEB)

    Pelicon, Primož, E-mail: primoz.pelicon@ijs.si [Jožef Stefan Institute, Association EURATOM-MHEST, Jamova 39, SI-1000 Ljubljana (Slovenia); Podaru, Nicolae C., E-mail: info@highvolteng.com [High Voltage Engineering Europa B.V., P.O. Box 99, Amersfoort 3800AB (Netherlands); Vavpetič, Primož; Jeromel, Luka [Jožef Stefan Institute, Association EURATOM-MHEST, Jamova 39, SI-1000 Ljubljana (Slovenia); Ogrinc Potocnik, Nina [Jožef Stefan Institute, Association EURATOM-MHEST, Jamova 39, SI-1000 Ljubljana (Slovenia); LOTRIČ Metrology ltd, Selca 163, SI-4227 Selca (Slovenia); Ondračka, Simon [Jožef Stefan Institute, Association EURATOM-MHEST, Jamova 39, SI-1000 Ljubljana (Slovenia); Gottdang, Andreas; Mous, Dirk J.M. [High Voltage Engineering Europa B.V., P.O. Box 99, Amersfoort 3800AB (Netherlands)

    2014-08-01

    Jožef Stefan Institute recently commissioned a high brightness H{sup −} ion beam injection system for its existing tandem accelerator facility. Custom developed by High Voltage Engineering Europa, the multicusp ion source has been tuned to deliver at the entrance of the Tandetron™ accelerator H{sup −} ion beams with a measured brightness of 17.1 A m{sup −2} rad{sup −2} eV{sup −1} at 170 μA, equivalent to an energy normalized beam emittance of 0.767 π mm mrad MeV{sup 1/2}. Upgrading the accelerator facility with the new injection system provides two main advantages. First, the high brightness of the new ion source enables the reduction of object slit aperture and the reduction of acceptance angle at the nuclear microprobe, resulting in a reduced beam size at selected beam intensity, which significantly improves the probe resolution for micro-PIXE applications. Secondly, the upgrade strongly enhances the accelerator up-time since H and He beams are produced by independent ion sources, introducing a constant availability of {sup 3}He beam for fusion-related research with NRA. The ion beam particle losses and ion beam emittance growth imply that the aforementioned beam brightness is reduced by transport through the ion optical system. To obtain quantitative information on the available brightness at the high-energy side of the accelerator, the proton beam brightness is determined in the nuclear microprobe beamline. Based on the experience obtained during the first months of operation for micro-PIXE applications, further necessary steps are indicated to obtain optimal coupling of the new ion source with the accelerator to increase the normalized high-energy proton beam brightness at the JSI microprobe, currently at 14 A m{sup −2} rad{sup −2} eV{sup −1}, with the output current at 18% of its available maximum.

  1. A Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-01-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher,

  2. Observations and diagnostics in high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Cianchi, A., E-mail: alessandro.cianchi@roma2.infn.it [University of Rome Tor Vergata and INFN-Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Anania, M.P.; Bisesto, F.; Castellano, M.; Chiadroni, E.; Pompili, R.; Shpakov, V. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy)

    2016-09-01

    The brightness is a figure of merit largely used in the light sources, like FEL (Free Electron Lasers), but it is also fundamental in several other applications, as for instance Compton backscattering sources, beam driven plasma accelerators and THz sources. Advanced diagnostics are essential tools in the development of high brightness beams. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement.

  3. Accelerator Layout and Physics of X-Ray Free-Electron Lasers

    CERN Document Server

    Decking, W

    2005-01-01

    X-ray Free-Electron Lasers facilities are planned or already under construction around the world. This talk covers the X-Ray Free-Electron Lasers LCLS (SLAC), European XFEL (DESY) and SCSS (Spring8). All aim for self-amplified spontaneous emission (SASE) FEL radiation of approximately 0.1 nm wavelengths. The required excellent electron beam qualities pose challenges to the accelerator physicists. Space charge forces, coherent synchrotron radiation and wakefields can deteriorate the beam quality. The accelerator physics and technological challenges behind each of the projects will be reviewed, covering the critical components low-emittance electron gun, bunch-compressors, accelerating structures and undulator systems.

  4. High-Brightness High-Energy Electron Beams from a Laser Wakefield Accelerator via Energy Chirp Control

    Science.gov (United States)

    Wang, W. T.; Li, W. T.; Liu, J. S.; Zhang, Z. J.; Qi, R.; Yu, C. H.; Liu, J. Q.; Fang, M.; Qin, Z. Y.; Wang, C.; Xu, Y.; Wu, F. X.; Leng, Y. X.; Li, R. X.; Xu, Z. Z.

    2016-09-01

    By designing a structured gas density profile between the dual-stage gas jets to manipulate electron seeding and energy chirp reversal for compressing the energy spread, we have experimentally produced high-brightness high-energy electron beams from a cascaded laser wakefield accelerator with peak energies in the range of 200-600 MeV, 0.4%-1.2% rms energy spread, 10-80 pC charge, and ˜0.2 mrad rms divergence. The maximum six-dimensional brightness B6 D ,n is estimated as ˜6.5 ×1 015 A /m2/0.1 % , which is very close to the typical brightness of e beams from state-of-the-art linac drivers. These high-brightness high-energy e beams may lead to the realization of compact monoenergetic gamma-ray and intense coherent x-ray radiation sources.

  5. Initial observations of high-charge, low-emittance electron beams at HIBAF (High Brightness Accelerator FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Carsten, B.E.; Feldman, D.W.; Sheffield, R.L.; Stein, W.E.; Johnson, W.J.; Thode, L.E.; Bender, S.C.; Busch, G.E.

    1990-01-01

    We report our initial measurements of bright (high-charge, low-emittance) electron beams generated at the Los Alamos High Brightness Accelerator FEL (HIBAF) Facility. Normalized emittance values of less than 50 {pi} mm-mrad for charges ranging from 0.7 to 8.7 nC were obtained for single micropulses at a y-waist and at an energy of 14.7 MeV. These measurements were part of the commissioning campaign on the HIBAF photoelectric injector. Macropulse measurements have also been performed and are compared with PARMELA simulations. 5 refs., 8 figs., 3 tabs.

  6. High brightness gamma-ray production at Fermilab Accelerator Science and Technology (FAST) facility

    Science.gov (United States)

    Mihalcea, D.; Jacobson, B.; Murokh, A.; Piot, P.; Ruan, J.

    2017-03-01

    Electron beams with energies of the order of a few 100's of MeV and low transverse emittance, in combination with powerful infrared lasers, allow for the production of high quality gamma rays through Inverse Compton Scattering (ICS). At Fermilab Accelerator Science and Technology (FAST) facility, a 300 MeV beam will be used to generate gamma rays with maximum photon energies of up to ˜1.5 MeV and brightness of the order of 1021 photons/[s-(mm-mrad)2- 0.1%BW]. Due to the low electron-beam transverse emittance, the relative bandwidth of the scattered radiation is expected to be ≤ 1%. A key challenge toward the production of high radiation dose and brightness is to enhance the energy of the infrared 3 ps laser pulses to the joule level. In this contribution, we present the plans for the experimental setup, along with comprehensive numerical simulations of the ICS process.

  7. Time-interleaved multienergy acceleration for an x-ray free-electron laser facility

    Directory of Open Access Journals (Sweden)

    Toru Hara

    2013-08-01

    Full Text Available To meet the demand from the growing number of user experiments, multi-beam-line operation with a wide spectral range is seriously considered in x-ray free-electron laser facilities. In a conventional design, the beam line of low photon energies branches off from the middle of the accelerator to take out low energy electron beams. Here in this paper, a novel method is proposed to deliver bunch-to-bunch energy changed electron beams at the end of the accelerator. Since all accelerator components are operated in steady state, this method enables quasisimultaneous operation of multi-beam-line in the same undulator hall without degrading the stability and performance of the electron beam.

  8. A low-energy-spread rf accelerator for a far-infrared free electron laser

    Science.gov (United States)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-10-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher, a buncher and two standard commercial linac sections. The gun is operated with a pulse duration of 280 ps and a bunch charge of 200 pC. After compression to 35 ps by the prebuncher, the bunches are accelerated to 4 MeV in the buncher and simultaneously compressed to 6 ps. The principle of the method is that the order of the electrons is conserved in the buncher, so that the resulting more or less linear energy-phase relationship along each bunch can be compensated effectively against space charge forces and the accelerating field gradient in the linacs, via an appropriate choice of the phase of the rf wave. Behind the linacs an rms energy spread of 0.30% has been measured.

  9. High Brightness Gamma-Ray Production at Fermilab Accelerator Science and Technology (FAST) Facility

    Energy Technology Data Exchange (ETDEWEB)

    Mihalcea, Daniel [Northern Illinois U.; Jacobson, B. [RadiaBeam Tech.; Murokh, A. [RadiaBeam Tech.; Piiot, P. [Northern Illinois U.; Ruan, J. [Fermilab

    2016-10-10

    Electron beams with energies of the order of a few 100’s of MeV and low transverse emittance, in combination with powerful infrared lasers, allow for the production of high quality gamma rays through Inverse Compton Scattering (ICS). At Fermilab Accelerator Science and Technology (FAST) facility, a 300 MeV beam will be used to generate gamma rays with maximum photon energies of up to ∼ 1.5 MeV and brightness of the order of 1021 photons/[s-(mm-mrad)2- 0.1%BW]. Due to the low electron-beam transverse emittance, the relative bandwidth of the scattered radiation is expected to be ≤ 1%. A key challenge toward the production of high radiation dose and brightness is to enhance the energy of the infrared 3 ps laser pulses to the joule level. In this contribution, we present the plans for the experimental setup, along with comprehensive numerical simulations of the ICS process.

  10. Compact beam transport system for free-electron lasers driven by a laser plasma accelerator

    Science.gov (United States)

    Liu, Tao; Zhang, Tong; Wang, Dong; Huang, Zhirong

    2017-02-01

    Utilizing laser-driven plasma accelerators (LPAs) as a high-quality electron beam source is a promising approach to significantly downsize the x-ray free-electron laser (XFEL) facility. A multi-GeV LPA beam can be generated in several-centimeter acceleration distance, with a high peak current and a low transverse emittance, which will considerably benefit a compact FEL design. However, the large initial angular divergence and energy spread make it challenging to transport the beam and realize FEL radiation. In this paper, a novel design of beam transport system is proposed to maintain the superior features of the LPA beam and a transverse gradient undulator (TGU) is also adopted as an effective energy spread compensator to generate high-brilliance FEL radiation. Theoretical analysis and numerical simulations are presented based on a demonstration experiment with an electron energy of 380 MeV and a radiation wavelength of 30 nm.

  11. Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

    Science.gov (United States)

    Serpico, C.; Grudiev, A.; Vescovo, R.

    2016-10-01

    Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted.

  12. High Power Amplifiers Chain nonlinearity influence on the accelerating beam stability in free electron laser (FLASH)

    CERN Document Server

    Cichalewski, w

    2010-01-01

    The high power amplifiers transfer characteristics nonlinearities can have a negative influence on the overall system performance. This is also true for the TESLA superconducting cavities accelerating field parameters control systems. This Low Level Radio Frequency control systems uses microwave high power amplifiers (like 10 MW klystrons) as actuators in the mentioned feedback loops. The amplitude compression and phase deviations phenomena introduced to the control signals can reduce the feedback performance and cause electron beam energy instabilities. The transfer characteristics deviations in the Free Electron Laser in Hamburg experiment have been investigated. The outcome of this study together with the description of the developed linearization method based on the digital predistortion approach have been described in this paper. Additionally, the results from the linearization tool performance tests in the FLASH's RF systems have been placed.

  13. STUDIES OF A FREE ELECTRON LASER DRIVEN BY A LASER-PLASMA ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.; Schroeder, C.; Fawley, W.

    2008-01-01

    A free electron laser (FEL) uses an undulator, a set of alternating magnets producing a periodic magnetic fi eld, to stimulate emission of coherent radiation from a relativistic electron beam. The Lasers, Optical Accelerator Systems Integrated Studies (LOASIS) group at Lawrence Berkeley National Laboratory (LBNL) will use an innovative laserplasma wakefi eld accelerator to produce an electron beam to drive a proposed FEL. In order to optimize the FEL performance, the dependence on electron beam and undulator parameters must be understood. Numerical modeling of the FEL using the simulation code GINGER predicts the experimental results for given input parameters. Among the parameters studied were electron beam energy spread, emittance, and mismatch with the undulator focusing. Vacuum-chamber wakefi elds were also simulated to study their effect on FEL performance. Energy spread was found to be the most infl uential factor, with output FEL radiation power sharply decreasing for relative energy spreads greater than 0.33%. Vacuum chamber wakefi elds and beam mismatch had little effect on the simulated LOASIS FEL at the currents considered. This study concludes that continued improvement of the laser-plasma wakefi eld accelerator electron beam will allow the LOASIS FEL to operate in an optimal regime, producing high-quality XUV and x-ray pulses.

  14. STUDIES OF A FREE ELECTRON LASER DRIVEN BY A LASER-PLASMA ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.; Schroeder, C.; Fawley, W.

    2008-01-01

    A free electron laser (FEL) uses an undulator, a set of alternating magnets producing a periodic magnetic fi eld, to stimulate emission of coherent radiation from a relativistic electron beam. The Lasers, Optical Accelerator Systems Integrated Studies (LOASIS) group at Lawrence Berkeley National Laboratory (LBNL) will use an innovative laserplasma wakefi eld accelerator to produce an electron beam to drive a proposed FEL. In order to optimize the FEL performance, the dependence on electron beam and undulator parameters must be understood. Numerical modeling of the FEL using the simulation code GINGER predicts the experimental results for given input parameters. Among the parameters studied were electron beam energy spread, emittance, and mismatch with the undulator focusing. Vacuum-chamber wakefi elds were also simulated to study their effect on FEL performance. Energy spread was found to be the most infl uential factor, with output FEL radiation power sharply decreasing for relative energy spreads greater than 0.33%. Vacuum chamber wakefi elds and beam mismatch had little effect on the simulated LOASIS FEL at the currents considered. This study concludes that continued improvement of the laser-plasma wakefi eld accelerator electron beam will allow the LOASIS FEL to operate in an optimal regime, producing high-quality XUV and x-ray pulses.

  15. Design and operation of an inverse free-electron-laser accelerator in the microwave regime

    Science.gov (United States)

    Yoder, Rodney Bruce

    2000-09-01

    A novel electron accelerator demonstrating the inverse free-electron-laser (IFEL) principle has been designed, built, and operated using radio-frequency power at 2.856 GHz. Such an accelerator uses a stationary, periodic magnetic field to impart transverse motion to charged particles, which are then accelerated by guided electromagnetic waves. The experiment described here demonstrates for the first time the phase dependence of IFEL acceleration. This design uses up to 15 MW of RF power propagating in a smooth-walled circular waveguide surrounded by a pulsed bifilar helical undulator; an array of solenoids provides an axial guiding magnetic field undulator; pitch, which is initially 11.75 cm, is linearly increased to 12.3 cm. over the 1-meter length of the structure to maintain acceleration gradient. Numerical computations predict an energy gain of up to 0.7 MeV using a 6 MeV injected beam from a 2-1/2 cell RF gun, with small energy spread and strong phase trapping. The initial injection phase is the most important parameter, determining the rate of energy gain or loss. These simulations are compared with experimental measurements at low power in which electron beams at energies between 5 and 6 MeV gain up to 0.35 MeV with minimal energy spread, all exiting particles having been accelerated. The predicted phase sensitivity of the mechanism is verified, with beams injected into accelerating phases gaining energy cleanly while those injected into ``decelerating'' phases are shown to be degraded in quality and hardly changed in energy, demonstrating the asymmetry of a tapered-wiggler design. Agreement with simulation is very good for accelerating phases, though less exact otherwise. Scaling to higher power and frequency is investigated. The maximum attainable acceleration gradient for a MIFELA using 150 MW of RF power at 34 GHz is estimated to be at least 30 MV/m, and laser IFELs could conceivably reach gradients in the GeV/m range.

  16. Extremely High Current, High-Brightness Energy Recovery Linac

    CERN Document Server

    Ben-Zvi, Ilan; Beavis, Dana; Blaskiewicz, Michael; Bluem, Hans; Brennan, Joseph M; Burger, Al; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Cole, Michael; Connolly, Roger; Delayen, Jean R; Favale, Anthony; Gassner, David M; Grimes, Jacob T; Hahn, Harald; Hershcovitch, Ady; Holmes, Douglas; Hseuh Hsiao Chaun; Johnson, Peter; Kayran, Dmitry; Kewisch, Jorg; Kneisel, Peter; Lambiase, Robert; Litvinenko, Vladimir N; McIntyre, Gary; Meng, Wuzheng; Nehring, Thomas; Nicoletti, Tony; Oerter, Brian; Pate, David; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Roser, Thomas; Russo, Thomas; Scaduto, Joseph; Schultheiss, Tom; Segalov, Zvi; Smith, Kevin T; Todd, Alan M M; Warren-Funk, L; Williams, Neville; Wu, Kuo-Chen; Yakimenko, Vitaly; Yip, Kin; Zaltsman, Alex; Zhao, Yongxiang

    2005-01-01

    Next generation ERL light-sources, high-energy electron coolers, high-power Free-Electron Lasers, powerful Compton X-ray sources and many other accelerators were made possible by the emerging technology of high-power, high-brightness electron beams. In order to get the anticipated performance level of ampere-class currents, many technological barriers are yet to be broken. BNL's Collider-Accelerator Department is pursuing some of these technologies for its electron cooling of RHIC application, as well as a possible future electron-hadron collider. We will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun and an accelerator cavity capable of producing low emittance (about 1 micron rms normalized) one nano-Coulomb bunches at currents of the order of one ampere average.

  17. Emittance measurement of high-brightness microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Ishizuka, Hiroshi; Nakahara, Yuriko (Fukuoka Inst. of Tech. (Japan)); Kawasaki, Sunao; Musyoki, S.; Shimizu, Hiroshi; Watanabe, Akihiko; Shiho, Makoto

    1994-09-01

    Arrays of microtriodes have recently become available due to the development of microfabricated field-emission electron sources. Computer simulation has shown that the brightness of beams emitted by them is significantly higher than that of the common microbeams, and possible application of the accelerated beam to free electron lasers has been discussed. Experimentation on beam generation has started, but methods for diagnosing the beam have not yet been established. Difficulty is predicted, because of the high brightness, in applying the conventional methods of emittance measurement. In this paper we propose a new method that determines the emittance without using apertures. The cross section of a converging beam is elongated by a quadrupole lens, and parameters of the emittance ellipse are obtained from the beam size on a screen when changing either the strength or the axial position of the quadrupole lens. (author).

  18. The Los Alamos high-brightness photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    O' Shea, P.G.

    1991-01-01

    For a number of years Los Alamos National Laboratory has been developing photocathode RF guns for high-brightness electron beam applications such as free-electron lasers (FELs). Previously thermionic high-voltage guns have been the source of choice for the electron accelerators used to drive FELs. The performance of such FELs is severely limited by the emittance growth produced by the subharmonic bunching process and also by the low peak current of the source. In a photoinjector, a laser driven photocathode is placed directly in a high-gradient RF accelerating cavity. A photocathode allows unsurpassed control over the current, and the spatial and temporal profile of the beam. In addition the electrodeless emission'' avoids many of the difficulties associated with multi-electrode guns, i.e. the electrons are accelerated very rapidly to relativistic energies, and there are no electrodes to distort the accelerating fields. For the past two years we have been integrating a photocathode into our existing FEL facility by replacing our thermionic gun and subharmonic bunchers with a high-gradient 1.3 GHz photoinjector. The photoinjector, which is approximately 0.6 m in length, produces 6 MeV, 300 A, 15 ps linac, and accelerated to a final energy of 40 MeV. We have recently begun lasing at wavelengths near 3 {mu}m. 16 refs., 2 figs., 5 tabs.

  19. First measurements of electron-beam transit times and micropulse elongation in a photoelectric injector at the High-Brightness Accelerator FEL (HIBAF)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Carlsten, B.E.; Feldman, R.B.

    1990-01-01

    Key aspects of the dynamics of a photoelectric injector (PEI) on the Los Alamos High-Brightness Accelerator FEL (HIBAF) facility have been investigated using a synchroscan streak camera. By phase-locking the streak camera sweep to the reference 108.3 MHz rf signal, the variations of micropulse temporal elongations (30 to 80% over the drive-laser pulse length) and of transit times (25 ps for a 16{degree}-phase change) were observed for the first time. These results were in good agreement with PARMELA simulations. 2 refs., 8 figs.

  20. An accelerator scenario for hard X-ray free electron laser joint with high energy electron radiography

    CERN Document Server

    Wei, Tao; Yang, Guojun; Pang, Jian; Li, Yuhui; Li, Peng; Pflueger, Joachim; He, Xiaozhong; Lu, Yaxing; Wang, Ke; Long, Jidong; Zhang, Linwen; Wu, Qiang

    2016-01-01

    In order to study the dynamic response of the material and the physical mechanism of the fluid dynamics, an accelerator scenario which can be applied to hard X-ray free electron laser and high energy electron radiography was proposed. This accelerator is mainly composed of a 12GeV linac, an undulator branch and an eRad beamline. In order to characterize sample's dynamic behavior in situ and real-time with XFEL and eRad simultaneously, the linac should be capable of accelerating the two kinds of beam within the same operation mode. Combining with in-vacuum and tapering techniques, the undulator branch can produce more than 1E11 photons per pulse in 0.1 precent bandwidth at 42keV. Finally, the eRad amplifying beamline with 1:10 ratio was proposed as an important complementary tool for the wider view field and density identification ability.

  1. Compact x-ray free-electron laser from a laser-plasma accelerator using a transverse-gradient undulator.

    Science.gov (United States)

    Huang, Zhirong; Ding, Yuantao; Schroeder, Carl B

    2012-11-16

    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 free-electron laser (FEL) radiation generation. 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 self-amplified spontaneous emission and seeded extreme ultraviolet and soft x-ray FELs based on laser plasma accelerators.

  2. Frequency mixing in accelerator based sources and application to tunable seeded free-electron lasers

    Directory of Open Access Journals (Sweden)

    C. Evain

    2014-12-01

    Full Text Available In this article we address the problem of tunability of seeded free-electron lasers (FELs, working typically in the domain of the vacuum ultraviolet. The seeding of FELs with an external laser permits us to obtain FEL pulses with both good longitudinal coherence and good stability properties (contrary to an amplification starting from noise. However, with a fixed external laser wavelength, only amplification at harmonics of this wavelength is possible. If full tunability is wanted, it is necessary to have a tunable external source; but this type of source has much less power, hence it is much harder to reach high harmonics numbers. Here we propose the so-called frequency mixing scheme (from its analogy with the similar process in nonlinear optics, based on two laser/electron interactions. Numerical and analytic studies show that it permits to increase significantly the tunability at short wavelengths using a low-energy tunable source. Numerical simulations are made with the parameters of FERMI-FEL 1, the first seeded FEL for user operation.

  3. Development of free electron laser and accelerator technology in Poland (CARE and EuCARD projects)

    CERN Document Server

    Romaniuk, Ryszard

    2009-01-01

    The development of accelerator technology in Poland is strictly combined with the cooperation with specialist accelerator centers of global character, where the relevant knowledge is generated, allowing to build big and modern machines. These are relatively costly undertakings of interdisciplinary character. Most of them are financed from the local resources. Only the biggest machines are financed commonly by many nations like: LHC in CERN, ILC in Fermi Lab, E-XFEL in DESY. A similar financing solution has to be implemented in Poland, where a scientific and political campaign is underway on behalf of building two big machines, a Polish Synchrotron in Kraków and a Polish FEL in Świerk. Around these two projects, there are realized a dozen or so smaller ones.

  4. Design study of high gradient, low impedance accelerating structures for the FERMI free electron laser linac upgrade

    Science.gov (United States)

    Shafqat, N.; Di Mitri, S.; Serpico, C.; Nicastro, S.

    2017-09-01

    The FERMI free-electron laser (FEL) of Elettra Sincrotrone Trieste, Italy, is a user facility driven by a 1.5 GeV 10-50 Hz S-band radiofrequency linear accelerator (linac), and it is based on an external laser seeding scheme that allows lasing at the shortest fundamental wavelength of 4 nm. An increase of the beam energy to 1.8 GeV at a tolerable breakdown rate, and an improvement of the final beam quality is desired in order to allow either lasing at 4 nm with a higher flux, or lasing at shorter wavelengths. This article presents the impedance analysis of newly designed S-band accelerating structures, for replacement of the existing backward travelling wave structures (BTWS) in the last portion of the FERMI linac. The new structure design promises higher accelerating gradient and lower impedance than those of the existing BTWS. Particle tracking simulations show that, with the linac upgrade, the beam relative energy spread, its linear and nonlinear z-correlation internal to the bunch, and the beam transverse emittances can be made smaller than the ones in the present configuration, with expected advantage to the FEL performance. The repercussion of the upgrade on the linac quadrupole magnets setting, for a pre-determined electron beam optics, is also considered.

  5. High Brightness OLED Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, Jeffrey [OLEDWorks LLC; Kondakova, Marina [OLEDWorks LLC; Boroson, Michael [OLEDWorks LLC; Hamer, John [OLEDWorks LLC

    2016-05-25

    In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

  6. The Physics and Applications of High Brightness Electron Beams

    Science.gov (United States)

    Palumbo, Luigi; Rosenzweig, J.; Serafini, Luca

    2007-09-01

    Plenary sessions. RF deflector based sub-Ps beam diagnostics: application to FEL and advanced accelerators / D. Alesini. Production of fermtosecond pulses and micron beam spots for high brightness electron beam applications / S.G. Anderson ... [et al.]. Wakefields of sub-picosecond electron bunches / K.L.F. Bane. Diamond secondary emitter / I. Ben-Zvi ... [et al.]. Parametric optimization for an X-ray free electron laser with a laser wiggler / R. Bonifacio, N. Piovella and M.M. Cola. Needle cathodes for high-brightness beams / C.H. Boulware ... [et al.]. Non linear evolution of short pulses in FEL cascaded undulators and the FEL harmonic cascade / L. Giannessi and P. Musumeci. High brightness laser induced multi-meV electron/proton sources / D. Giulietti ... [et al.]. Emittance limitation of a conditioned beam in a strong focusing FEL undulator / Z. Huang, G. Stupakov and S. Reiche. Scaled models: space-charge dominated electron storage rings / R.A. Kishek ... [et al.]. High brightness beam applications: energy recovered linacs / G.A. Krafft. Maximizing brightness in photoinjectors / C. Limborg-Deprey and H. Tomizawa. Ultracold electron sources / O.J. Luiten ... [et al.]. Scaling laws of structure-based optical accelerators / A. Mizrahi, V. Karagodsky and L. Schächter. High brightness beams-applications to free-electron lasers / S. Reiche. Conception of photo-injectors for the CTF3 experiment / R. Roux. Superconducting RF photoinjectors: an overview / J. Sekutowicz. Status and perspectives of photo injector developments for high brightness beams / F. Stephan. Results from the UCLA/FNLP underdense plasma lens experiment / M.C. Thompson ... [et al.]. Medical application of multi-beam compton scattering monochromatic tunable hard X-ray source / M. Uesaka ... [et al.]. Design of a 2 kA, 30 fs RF-photoinjector for waterbag compression / S.B. Van Der Geer, O.J. Luiten and M.J. De Loos. Proposal for a high-brightness pulsed electron source / M. Zolotorev ... [et al

  7. Wake field of electron beam accelerated in a RF-gun of free electron laser 'ELSA'

    CERN Document Server

    Salah, W

    1999-01-01

    Wake field effects driven by a coasting relativistic charged particle beam have been studied for various cavity geometries. In the particular case of a cylindrical 'pill-box' cavity, an analytical expression of the (E, B)(x, t) map has been obtained as a development on the complete base cavity normal modes. We extend this method to the case of an accelerated beam, which leaves the downstream face of the cavity with a thermal velocity, and becomes relativistic in a few cm. This situation is very different from the classical wake of an ultrarelativistic beam for two reasons: (a) in the case of an ultrarelativistic beam, the field directly generated by beam particles in their wake can be neglected, and the so-called wake field is the electromagnetic linear response of the cavity to the exciting signal which is the beam. For a transrelativistic beam, the direct field must be taken into account and added to cavity response, which is no longer linear, except for low-intensity beam; (b) causality prevents any beam's...

  8. Electron acceleration in the inverse free electron laser with a helical wiggler by axial magnetic field and ion-channel guiding

    Institute of Scientific and Technical Information of China (English)

    Reza Khazaeinezhad; Mahdi Esmaeilzadeh

    2012-01-01

    Electron acceleration in the inverse free electron laser (IFEL) with a helical wiggler in the presence of ion-channel guiding and axial magnetic field is investigated in this article.The effects of tapering wiggler amplitude and axial magnetic field are calculated for the electron acceleration.In free electron lasers,electron beams lose energy through radiation while in IFEL electron beams gain energy from the laser.The equation of electron motion and the equation of energy exchange between a single electron and electromagnetic waves are derived and then solved numerically using the fourth order Runge-Kutta method.The tapering effects of a wiggler magnetic field on electron acceleration are investigated and the results show that the electron acceleration increases in the case of a tapered wiggler magnetic field with a proper taper constant.

  9. Design and characterization of the DC acceleration and transport system required for the FOM 1 MW free electron maser experiment

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. [Lawrence Livermore National Lab., CA (United States); Urbanus, W.H.; Geer, C. van der [FOM-Institut voor Plasma Fysica, Nieuwegein (Netherlands)] [and others

    1995-12-31

    A Free Electron Maser (FEM) has been constructed and is soon to be tested at the FOM Institute (Rijnhuizen) Netherlands with the goal of producing 1 MW long pulse to CW microwave output in the range 130 GHz to 250 GHz. The design uses a DC beam system in a depressed collector configuration in order to make the overall wall plug efficiency 50%. The high voltage ({approximately} 2 MeV) power supply provides only the body interception current ({approximately} 30 mA) while the 12 amp beam current is supplied by the 100-200 keV collector supplies. Some of the design features to ensure low interception current, which is critical to long pulse (CW) operation are: (1) DC beam in-line transport and acceleration system, (2) emittance conserving solenoid focusing system, (3) halo suppression techniques at cathode edge, and (4) very low beam fill factor (<20%). A relativistic version of the Herman Optical theory developed for microwave tubes is used to determine current distribution functions everywhere along the beam from the electron gun, through the DC accelerator and transport system to the wiggler. This theory takes into account thermals far out on the gaussian tail which translates into beam current far outside the ideal beam edge. This theory is applied to the FOM beam line design to predict a series of beam envelope contours containing various percentages of total beam current up to 99.9%. Predictions of body interception current due to finite emittance (effective temperature) are presented and compared with measured experimental results.

  10. High Repetition Rate Electron Beam RF-Acceleration and Sub-Millimeter Wave Generation Via a Free Electron Laser.

    Science.gov (United States)

    1986-02-14

    Period, Including Journal References: (a) D.B. McDermott, W.J. Nunan and N.C. Luhmann, Jr., "A High Duty Cycle, Compact 94 GHz Free Electron Laser...34 submitted to Journal IR and am-Waves. (b) W.J. Nunan , D.B. McDermott and N.C. Luhmann, Jr., "A High Repetition *Rate, Compact 94 GHz Free Electron Laser...34 Bulletin of the American Phy- * ) sical Society 30, 1543 (1985). L J (c) D.B. McDermott, W.J. Nunan and N.C. Luhmann, Jr., "A High RepetitionLL

  11. Operational experience on the generation and control of high brightness electron bunch trains at SPARC-LAB

    Science.gov (United States)

    Mostacci, A.; Alesini, D.; Anania, M. P.; Bacci, A.; Bellaveglia, M.; Biagioni, A.; Cardelli, F.; Castellano, Michele; Chiadroni, Enrica; Cianchi, Alessandro; Croia, M.; Di Giovenale, Domenico; Di Pirro, Giampiero; Ferrario, Massimo; Filippi, Francesco; Gallo, Alessandro; Gatti, Giancarlo; Giribono, Anna; Innocenti, L.; Marocchino, A.; Petrarca, M.; Piersanti, L.; Pioli, S.; Pompili, Riccardo; Romeo, Stefano; Rossi, Andrea Renato; Shpakov, V.; Scifo, J.; Vaccarezza, Cristina; Villa, Fabio; Weiwei, L.

    2015-05-01

    Sub-picosecond, high-brightness electron bunch trains are routinely produced at SPARC-LAB via the velocity bunching technique. Such bunch trains can be used to drive multi-color Free Electron Lasers (FELs) and plasma wake field accelerators. In this paper we present recent results at SPARC-LAB on the generation of such beams, highlighting the key points of our scheme. We will discuss also the on-going machine upgrades to allow driving FELs with plasma accelerated beams or with short electron pulses at an increased energy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-13

    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.

  13. Improving the energy-extraction efficiency of laser-plasma accelerator driven free-electron laser using transverse-gradient undulator with focusing optics and longitudinal tapering

    CERN Document Server

    Zhou, G; Wu, J; Zhang, T

    2016-01-01

    It is reported that [Z. Huang et al., Phys. Rev. Lett. 109, 204801 (2012)], high-gain free-electron laser (FEL) can be generated by transverse-dispersed electron beams from laser-plasma accelerators (LPAs) using transverse-gradient undulator (TGU) assuming an ideal constant dispersion function without focusing optics. The constant dispersion function keeps electrons beyond the resonant energy bandwidth still being on resonant with the FEL radiation. Instead, in this paper, the case with focusing optics in an LPA-driven FEL using TGU is numerically studied, in which the dispersion function should be monotonously decreasing along the undulator. Even though the FEL resonance is not always satisfied for off-energy electrons in this case, through subtly optimizing the initial dispersion and focusing parameters, it is feasible to achieve a similar radiation power to the case assuming an ideal constant dispersion function without focusing optics, and meanwhile, to attain a good transverse coherence. Moreover, higher...

  14. Proceedings of the NATO Advanced Study Institute on High-Brightness Accelerators Held in Pitlochry, Scotland on 13-25 July 1986. Series B. Volume 178

    Science.gov (United States)

    1986-07-25

    particle accelerators, Phys. Rev., 103:1837. Thomas, L.H., 1938 The paths of ions in the cyclotron, Phys. Rev., 54:580. TRIUMP , 1985 KAON factory...2assumptions that $* scales with energy as y and that at least approxi- mately az - Xrf - y in order to keep the total AC wall plug power for a collider with...efficiency with which it converts average input AC power into the electromagnetic power delivered to the structure. A figure of merit for the structure

  15. Measurements of the temporal and spatial phase variations of a 33 GHz pulsed free electron laser amplifier and application to high gradient RF acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Volfbeyn, P.; Bekefi, G. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-12-31

    We report the results of temporal and spatial measurements of phase of a pulsed free electron laser amplifier (FEL) operating in combined wiggler and axial guide magnetic fields. The 33 GHz FEL is driven by a mildly relativistic electron beam (750 kV, 90-300 A, 30 ns) and generates 61 MW of radiation with a high power magnetron as the input source. The phase is measured by an interferometric technique from which frequency shifting is determined. The results are simulated with a computer code. Experimental studies on a CERN-CLIC 32.98 GHz 26-cell high gradient accelerating section (HGA) were carried out for input powers from 0.1 MW to 35 MW. The FEL served as the r.f. power source for the HGA. The maximum power in the transmitted pulse was measured to be 15 MW for an input pulse of 35 MW. The theoretically calculated shunt impedance of 116 M{Omega}/m predicts a field gradient of 65 MeV/m inside the HGA. For power levels >3MW the pulse transmitted through the HGA was observed to be shorter than the input pulse and pulse shortening became more serious with increasing power input. At the highest power levels the output pulse length (about 5 nsec) was about one quarter of the input pulse length. Various tests suggest that these undesirable effects occur in the input coupler to the HGA. Light and X-ray production inside the HGA have been observed.

  16. High brightness semiconductor lasers with reduced filamentation

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.;

    1999-01-01

    High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture...

  17. Plasmon-enhanced photocathode for high brightness and high repetition rate x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, Aleksandr; Senft, Christoph; Thompson, K. F.; Feng, J.; Cabrini, S.; Schuck, P. J.; Padmore, Howard; Peppernick, Samuel J.; Hess, Wayne P.

    2013-02-11

    High brightness electron sources are at the heart of anew generation of x-ray sources based on the Free ElectronLaser (FEL) as well as in Energy Recovery Linac (ERL) and Inverse Compton Scattering (ICS) sources.The source of electrons consists of a photoinjector, comprised of a laser-driven photocathode in a high gradient electric field produced by an rf cavity. The function of the rf cavity is to provide a field sufficient for acceleration of electrons to relativistic velocity over a small distance, thus minimizing effects of the space-charge. Even so, the dense electron beam required for high brightness suffers from a space charge field that chirps and reshapes the electron pulse increasing beam emittance and thus reducing the overall brightness. This emittance growth can be avoided if the initial distribution of electrons is pancake shaped, with a semicircular transverse intensity profile. In this case, the electron distribution develops under its space charge field from a pancake into a uniformly filled ellipsoidal beam. This condition, referred to as the blowout regime, requires ultrashort pulses less than 100 fs long and has been successfully demonstrated recently in a high gradient photoinjector.

  18. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    Science.gov (United States)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  19. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source.

    Science.gov (United States)

    Wells, R P; Ghiorso, W; Staples, J; Huang, T M; Sannibale, F; Kramasz, T D

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  20. A free-electron laser in the pulsar magnetosphere

    NARCIS (Netherlands)

    Fung, P.K.; Kuijpers, J.M.E.

    2004-01-01

    We have studied systematically the free-electron laser in the context of high brightness pulsar radio emission. In this paper, we have numerically examined the case where a transverse electromagnetic wave is distorting the motion of a relativistic electron beam while travelling over one stellar radi

  1. The Study of Advanced Accelerator Physics Research at UCLA Using the ATF at BNL: Vacuum Acceleration by Laser of Free Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Cline, David B. [Univ. of California, Los Angeles, CA (United States)

    2016-09-07

    An experiment was designed and data were taken to demonstrate that a tightly focused laser on vacuum can accelerate an electron beam in free space. The experiment was proof-of-principle and showed a clear effect for the laser beam off and on. The size of the effect was about 20% and was consistent over 30 laser and beam shots.

  2. The Study of Advanced Accelerator Physics Research at UCLA Using the ATF at BNL: Vacuum Acceleration by Laser of Free Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Cline, David B. [Univ. of California, Los Angeles, CA (United States)

    2016-09-07

    An experiment was designed and data taken to demonstrate that a tightly focused laser on vacuum can accelerate an electron beam in free space. The experiment was proof-of-principle and showed a clear effect for the laser beam off and on. The size of the effect was about 20% and was consistent over 30 laser and beam shots.

  3. ECR Ion Source for a High-Brightness Cyclotron

    Science.gov (United States)

    Comeaux, Justin; McIntyre, Peter; Assadi, Saeed

    2011-10-01

    New technology is being developed for high-brightness, high-current cyclotrons with performance benefits for accelerator-driven subcritical fission power, medical isotope production, and proton beam cancer therapy. This paper describes the design for a 65 kV electron cyclotron resonance (ECR) ion source that will provide high-brightness beam for injection into the cyclotron. The ion source is modeled closely upon the one that is used at the Paul Scherrer Institute. Modifications are being made to provide enhanced brightness and compatibility for higher-current operation.

  4. Free Electron Laser in Poland

    CERN Document Server

    Romaniuk, Ryszard

    2009-01-01

    The idea of building a new IVth generation of light sources of high luminosity, which use accelerators, arose in the 80ties of XXth century. Now, in a numerable synchrotron and laser laboratories in Europe, there is carried out, since a couple of years, intense applied research on free electron lasers (FEL) [17,18]. Similarly, in this country, free electron laser in Poland – POLFEL [9] is, in a design, a coherent light source of the IVth generation, characterized by very short pulses in the range of 10-100fs, of big power 0,2GW and UV wavelength of 27nm, of average power 1W, with effective high power third harmonic of 9nm. The laser consists of a linear superconducting accelerator 100m in length, undulator and experimental lines. It generates a monochromatic and coherent radiation and can be tuned from THz range via IR, visible to UV, and potentially to X-rays. The linac works in quasi-CW or real-CW mode. It is planned by IPJ [9,10] and XFEL-Poland Consortium [16] as a part of the ESFRI [1] priority EuroFEL...

  5. Applications for Energy Recovering Free Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    George Neil

    2007-08-01

    The availability of high-power, high-brilliance sources of tunable photons from energy-recovered Free Electron Lasers is opening up whole new fields of application of accelerators in industry. This talk will review some of the ideas that are already being put into production, and some of the newer ideas that are still under development.

  6. High-power beam injectors for 100 KW free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Todd, A. M. (Alan M.); Wood R. L. (Richard L.); Bluem, H.; Young, L. M. (Lloyd M.); Wiseman, M. (Mark); Schultheiss, T. (Thomas); Schrage, D. L. (Dale L.); Russell, S. J. (Steven J.); Rode, C. H.; Rimmer, R. (Robert); Nguyen, D. C. (Dinh C.); Kelley, J. P. (John Patrick); Kurennoy, S. (Sergey); wood, r

    2003-01-01

    A key technology issue on the path to high-power FEL operation is the demonstration of reliable, high-brightness, high-power injector operation. We describe two ongoing programs to produce 100 mA injectors as drivers for 100 kW free-electron lasers. In one approach, in collaboration with the Thomas Jefferson National Accelerator Facility, we are fabricating a 750 MHz superconducting RF cryomodule that will be integrated with a room-temperature DC photocathode gun and tested at the Laboratory. In the other approach, in collaboration with Los Alamos National Laboratory, a high-current 700 MHz, normal-conducting, RF photoinjector is being designed and will undergo thermal management testing at the Laboratory. We describe the design, the projected performance and the status of both injectors.

  7. Experimental Characterization Of The Saturating, Near Infrared, Self-amplified Spontaneous Emission Free Electron Laser Analysis Of Radiation Properties And Electron Beam Dynamics

    CERN Document Server

    Murokh, A

    2002-01-01

    In this work, the main results of the VISA experiment (Visible to Infrared SASE Amplifier) are presented and analyzed. The purpose of the experiment was to build a state-of-the-art single pass self-amplified spontaneous emission (SASE) free electron laser (FEL) based on a high brightness electron beam, and characterize its operation, including saturation, in the near infrared spectral region. This experiment was hosted by Accelerator Test Facility (ATF) at Brookhaven National Laboratory, which is a users facility that provides high brightness relativistic electron beams generated with the photoinjector. During the experiment, SASE FEL performance was studied in two regimes: a long bunch, lower gain operation; and a short bunch high gain regime. The transition between the two conditions was possible due to a novel bunch compression mechanism, which was discovered in the course of the experiment. This compression allowed the variation of peak current in the electron beam before it was launched into the 4-m VISA...

  8. Scattering parameters of the 3.9Â GHz accelerating module in a free-electron laser linac: A rigorous comparison between simulations and measurements

    Science.gov (United States)

    Flisgen, Thomas; Glock, Hans-Walter; Zhang, Pei; Shinton, Ian R. R.; Baboi, Nicoleta; Jones, Roger M.; van Rienen, Ursula

    2014-02-01

    This article presents a comparison between measured and simulated scattering parameters in a wide frequency interval for the third harmonic accelerating module ACC39 in the linear accelerator FLASH, located at DESY in Hamburg/Germany. ACC39 is a cryomodule housing four superconducting 3.9 GHz accelerating cavities. Due to the special shape of the cavities (in particular its end cells and the beam pipes) in ACC39, the electromagnetic field in the module is, in many frequency ranges, coupled from one cavity to the next. Therefore, the scattering parameters are determined by the entire string and not solely by the individual cavities. This makes the determination of the scattering properties demanding. As far as the authors can determine, this paper shows for the first time a direct comparison between state-of-the-art simulations and measurements of rf properties of long, complex, and asymmetric structures over a wide frequency band. Taking into account the complexity of the system and various geometrical unknowns, the agreement between experimental measurements and simulations is remarkably good for several distinct measurements, although a variety of effects (e.g. cavity deviations from the ideal shape or interactions with not modeled parts of the structure) is not considered in the computer simulation. After a short introduction, the paper provides detailed descriptions of simulations and experimental measurements performed at the module. In this context, the estimation of the cable properties is discussed as well. As a central part of the article, the comparison between measured and simulated transmission spectra and quality factors is presented. This study represents one of the first detailed comparisons between simulations and measurements for a coupled accelerator cavity system.

  9. Scattering parameters of the 3.9 GHz accelerating module in a free-electron laser linac: A rigorous comparison between simulations and measurements

    CERN Document Server

    Flisgen, T; Zhang, P; Shinton, I R R; Baboi, N; Jones, R M; van Rienen, U

    2014-01-01

    This article presents a comparison between measured and simulated scattering parameters in a wide frequency interval for the third harmonic accelerating module ACC39 in the linear accelerator FLASH, located at DESY in Hamburg/Germany. ACC39 is a cryomodule housing four superconducting 3.9  GHz accelerating cavities. Due to the special shape of the cavities (in particular its end cells and the beam pipes) in ACC39, the electromagnetic field in the module is, in many frequency ranges, coupled from one cavity to the next. Therefore, the scattering parameters are determined by the entire string and not solely by the individual cavities. This makes the determination of the scattering properties demanding. As far as the authors can determine, this paper shows for the first time a direct comparison between state-of-the-art simulations and measurements of rf properties of long, complex, and asymmetric structures over a wide frequency band. Taking into account the complexity of the system and various geometrical unk...

  10. A study of beam position diagnostics using beam-excited dipole modes in third harmonic superconducting accelerating cavities at a free-electron laser

    CERN Document Server

    Zhang, P; Jones, R M; Shinton, I R R; Flisgen, T; Glock, H W

    2012-01-01

    We investigate the feasibility of beam position diagnostics using Higher Order Mode (HOM) signals excited by an electron beam in the third harmonic 3.9 GHz superconducting accelerating cavities at FLASH. After careful theoretical and experimental assessment of the HOM spectrum, three modal choices have been narrowed down to fulfill different diagnostics requirements. These are localized dipole beam-pipe modes, trapped cavity modes from the fifth dipole band and propagating modes from the first two dipole bands. These modes are treated with various data analysis techniques: modal identification, direct linear regression (DLR) and singular value decomposition (SVD). Promising options for beam diagnostics are found from all three modal choices. This constitutes the first prediction, subsequently confirmed by experiments, of trapped HOMs in third harmonic cavities, and also the first direct comparison of DLR and SVD in the analysis of HOM-based beam diagnostics.

  11. A study of beam position diagnostics using beam-excited dipole modes in third harmonic superconducting accelerating cavities at a free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Pei [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Baboi, Nicoleta [Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Jones, Roger M.; Shinton, Ian R. R. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Cockcroft Institute, Cheshire WA4 4AD (United Kingdom); Flisgen, Thomas; Glock, Hans-Walter [Institut fuer Allgemeine Elektrotechnik, Universitaet Rostock, 18051 Rostock (Germany)

    2012-08-15

    We investigate the feasibility of beam position diagnostics using higher order mode (HOM) signals excited by an electron beam in the third harmonic 3.9 GHz superconducting accelerating cavities at FLASH. After careful theoretical and experimental assessment of the HOM spectrum, three modal choices have been narrowed down to fulfill different diagnostics requirements. These are localized dipole beam-pipe modes, trapped cavity modes from the fifth dipole band, and propagating modes from the first two dipole bands. These modes are treated with various data analysis techniques: modal identification, direct linear regression (DLR), and singular value decomposition (SVD). Promising options for beam diagnostics are found from all three modal choices. This constitutes the first prediction, subsequently confirmed by experiments, of trapped HOMs in third harmonic cavities, and also the first direct comparison of DLR and SVD in the analysis of HOM-based beam diagnostics.

  12. Undulators and free-electron lasers

    CERN Document Server

    Luchini, P

    1990-01-01

    This book is a reference text for all those working in free-electron laser research as well as being a learning aid for physicists and graduate students who wish an introduction to this field. Only a basic understanding of relativistic mechanics and electromagnetism is presupposed. After an overview of early developments and general principles of operation, the different models that can be used to describe free-electron lasers are presented, organized according to their range of applicability. The relevent conceptual and mathematical constructs are built up from first principles with attention to obtaining the practically important results in a simple but rigorous way. Interaction of the undulator with the driving electron accelerator and the laser cavity and design of undulator magnets are treated and an overview is given of some typical experiments.

  13. Synchrotron radiation and free-electron lasers principles of coherent X-ray generation

    CERN Document Server

    Kim, Kwang-Je; Lindberg, Ryan

    2017-01-01

    Learn about the latest advances in high-brightness X-ray physics and technology with this authoritative text. Drawing upon the most recent theoretical developments, pre-eminent leaders in the field guide readers through the fundamental principles and techniques of high-brightness X-ray generation from both synchrotron and free-electron laser sources. A wide range of topics is covered, including high-brightness synchrotron radiation from undulators, self-amplified spontaneous emission, seeded high-gain amplifiers with harmonic generation, ultra-short pulses, tapering for higher power, free-electron laser oscillators, and X-ray oscillator and amplifier configuration. Novel mathematical approaches and numerous figures accompanied by intuitive explanations enable easy understanding of key concepts, whilst practical considerations of performance-improving techniques and discussion of recent experimental results provide the tools and knowledge needed to address current research problems in the field. This is a comp...

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

    Directory of Open Access Journals (Sweden)

    F. Zhou

    2012-09-01

    Full Text Available Laser-based techniques have been widely used for cleaning metal photocathodes to increase quantum efficiency (QE. However, the impact of laser cleaning on cathode uniformity and thereby on electron beam quality are less understood. We are evaluating whether this technique can be applied to revive photocathodes used for high-brightness electron sources in advanced x-ray free-electron laser (FEL facilities, such as the Linac Coherent Light Source (LCLS at the SLAC National Accelerator Laboratory. The laser-based cleaning was applied to two separate areas of the current LCLS photocathode on July 4 and July 26, 2011, respectively. The QE was increased by 8–10 times upon the laser cleaning. Since the cleaning, routine operation has exhibited a slow evolution of the QE improvement and comparatively rapid improvement of transverse emittance, with a factor of 3 QE enhancement over five months, and a significant emittance improvement over the initial 2–3 weeks following the cleaning. Currently, the QE of the LCLS photocathode is holding constant at about 1.2×10^{-4}, with a normalized injector emittance of about 0.3  μm for a 150-pC bunch charge. With the proper procedures, the laser-cleaning technique appears to be a viable tool to revive the LCLS photocathode. We present observations and analyses for the QE and emittance evolution in time following the laser-based cleaning of the LCLS photocathode, and comparison to the previous studies, the measured thermal emittance versus the QE and comparison to the theoretical model.

  15. Biological applications of ultraviolet free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, J.C.

    1997-10-01

    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated.

  16. Material Processing Opportunites Utilizing a Free Electron Laser

    Science.gov (United States)

    Todd, Alan

    1996-11-01

    Many properties of photocathode-driven Free Electron Lasers (FEL) are extremely attractive for material processing applications. These include: 1) broad-band tunability across the IR and UV spectra which permits wavelength optimization, depth deposition control and utilization of resonance phenomena; 2) picosecond pulse structure with continuous nanosecond spacing for optimum deposition efficiency and minimal collateral damage; 3) high peak and average radiated power for economic processing in quantity; and 4) high brightness for spatially defined energy deposition and intense energy density in small spots. We discuss five areas: polymer, metal and electronic material processing, micromachining and defense applications; where IR or UV material processing will find application if the economics is favorable. Specific examples in the IR and UV, such as surface texturing of polymers for improved look and feel, and anti-microbial food packaging films, which have been demonstrated using UV excimer lamps and lasers, will be given. Unfortunately, although the process utility is readily proven, the power levels and costs of lamps and lasers do not scale to production margins. However, from these examples, application specific cost targets ranging from 0.1=A2/kJ to 10=A2/kJ of delivered radiation at power levels from 10 kW to 500 kW, have been developed and are used to define strawman FEL processing systems. Since =46EL radiation energy extraction from the generating electron beam is typically a few percent, at these high average power levels, economic considerations dictate the use of a superconducting RF accelerator with energy recovery to minimize cavity and beam dump power loss. Such a 1 kW IR FEL, funded by the US Navy, is presently under construction at the Thomas Jefferson National Accelerator Facility. This dual-use device, scheduled to generate first light in late 1997, will test both the viability of high-power FELs for shipboard self-defense against cruise

  17. High Brightness Neutron Source for Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J. T.; Piestrup, Melvin, A.; Gary, Charles, K.; Harris, Jack, L. Williams, David, J.; Jones, Glenn, E.; Vainionpaa, J. , H.; Fuller, Michael, J.; Rothbart, George, H.; Kwan, J., W.; Ludewigt, B., A.; Gough, R.., A..; Reijonen, Jani; Leung, Ka-Ngo

    2008-12-08

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  18. Proposal for Research on High-Brightness Cathodes for High-Power Free-Electron Lasers (FEL)

    Science.gov (United States)

    2013-05-09

    diamond field-emitter array (DFEA). The second is the gridded thermionic cathode, based on the development of gridded cathodes for high-power microwave ...possible as a method of increasing current density in exchange for higher turn-on field. Oxidation and deposition Diamond seeding : We now utilize...atmosphere or vacuum (~107 Torr) after the initial heat treatment results in performance that is slightly lower than that for operation at 450°C. This

  19. A high-brightness thermionic microwave electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Borland, Michael [Stanford Univ., CA (United States)

    1991-02-01

    In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun`s performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ``State-of-the-art`` microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 π • mec • μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 109e- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 π • me • μm.

  20. The vacuum system of the European X-ray free electron laser XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Zapfe, K; Boehnert, M; Hensler, O; Hoppe, D; Mildner, N; Nagorny, B; Rehlich, K; Remde, H; Wagner, A; Wohlenberg, T; Wojtkiewicz, J [Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany)], E-mail: kirsten.zapfe@desy.de

    2008-03-01

    The European X-ray Free Electron Laser XFEL, a new international research facility, will be built at DESY/Hamburg. The XFEL will generate extremely brilliant and ultra short pulses of spatially coherent X-rays with tuneable wavelengths down to 0.1 nm, and exploit them for revolutionary scientific experiments at various disciplines. The basic process adopted to produce the X-ray pulses is SASE (Self-Amplified Spontaneous Emission). Therefore electron bunches are produced in a high-brightness gun, brought to high energy of about 20 GeV through a superconducting linear accelerator, and transported to up to 250 m long undulators, where the X-rays are generated. The beam vacuum system of the accelerator contains sections operated at room temperature as well as at 2 K in the areas of the superconducting accelerating structures, thus requiring an insulating vacuum system. In addition to standard UHV requirements, the vacuum system for this facility needs to preserve the cleanliness of the superconducting cavity surfaces. Therefore the preparation of all vacuum components for the 1.6 km long main linac includes cleaning of the components in a clean room to remove particles, installation into the accelerator in local clean rooms, and special procedures for pump down and venting. Further challenges are the undulator vacuum chambers filling more than 700 m, where a high surface quality with respect to surface roughness and thickness of oxide layers is mandatory to reduce wake field effects, and the vacuum systems for the various beam dumps, where exit windows acting as vacuum barriers of sufficient reliability need to be developed. In addition, a large amount of about 1.7 km of transport beam lines is required. The layout of the various vacuum sections as well as experience with prototype components will be described.

  1. Design Studies for a VUV--Soft X-ray Free-Electron Laser Array

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.; Baptiste, K.; Byrd, J.M.; Denes, P.; Falcone, R.; Kirz, J.; McCurdy, W.; Padmore, H.; Penn, G.; Qiang, J.; Robin, D.; Sannibale, F.; Schoenlein, R.; Staples, J.; Steier, C.; Venturnini, M.; Wan, W.; Wells, R.; Wilcox, R.; Zholents, A.

    2009-08-04

    Several recent reports have identified the scientific requirements for a future soft X-ray light source [1, 2, 3, 4, 5], and a high-repetition-rate free-electron laser (FEL) facility responsive to them is being studied at Lawrence Berkeley National Laboratory (LBNL) [6]. The facility is based on a continuous-wave (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 the experimental requirements, the individualFELs may be configured for either self-amplified spontaneous emission (SASE), seeded highgain harmonic generation (HGHG), echo-enabled harmonic generation (EEHG), or oscillator mode of operation, and will produce high peak and average brightness x-rays with a flexible pulse format ranging from sub-femtoseconds to hundreds of femtoseconds. This new light source would serve a broad community of scientists in many areas of research, similar to existing utilization of storage ring based light sources. To reduce technical risks and constructioncosts, accelerator research, development, and design studies at LBNL target the most critical components and systems of the facility. We are developing a high-repetition-rate low-emittance electron gun, high quantum efficiency photocathodes, and have embarked on design and optimization of the electron beam accelerator, FEL switchyard, and array of FELs. We continue our work on precision timing and synchronization systems critical for time-resolved experiments using pump-probe techniques.

  2. Resonator design for a visible wavelength free-electron laser (*)

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, A.; Lordi, N. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.); Ben-Zvi, I.; Gallardo, J. (Brookhaven National Lab., Upton, NY (United States))

    1990-01-01

    Design requirements for a visible wavelength free-electron laser being developed at the Accelerator Test Facility at Brookhaven National Laboratory are presented along with predictions of laser performance from 3-D numerical simulations. The design and construction of the optical resonator, its alignment and control systems are also described. 15 refs., 8 figs., 4 tabs.

  3. Design and Analysis of Megawatt Class Free Electron Laser Weapons

    Science.gov (United States)

    2015-12-01

    25 H. THERMAL BLOOMING .......................................................................25 V. FREE ELECTRON LASER AND... thermal blooming. .................................................26 Figure 11. FEL 4-D model simulating an FEL oscillator configuration...nanoseconds apart . By contrast, normal conducting linear accelerators can only operate with microseconds-long macro-pulses separated by milliseconds due to

  4. A racetrack microtron with high brightness beams

    Science.gov (United States)

    Shvedunov, V. I.; Barday, R. A.; Frolov, D. A.; Gorbachev, V. P.; Gribov, I. V.; Knapp, E. A.; Novikov, G. A.; Pakhomov, N. I.; Shvedunov, I. V.; Skachkov, V. S.; Sobenin, N. P.; Trower, W. P.; Tyurin, S. A.; Vetrov, A. A.; Yailijan, V. R.; Zayarny, D. A.

    2004-10-01

    Here we describe a racetrack microtron that provides electron beams at 12 energies from 4.85 to 34.2 MeV with ˜150 pC/bunch in ˜5 ps bunches having ˜10 mm mrad normalized transverse emittance. Our compact, inexpensive accelerator in addition to its external electron beams can generate electromagnetic radiation from ˜3 mm to ˜0.3 nm by a variety of mechanisms.

  5. A racetrack microtron with high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Shvedunov, V.I.; Barday, R.A.; Frolov, D.A.; Gorbachev, V.P.; Gribov, I.V.; Knapp, E.A.; Novikov, G.A.; Pakhomov, N.I.; Shvedunov, I.V.; Skachkov, V.S.; Sobenin, N.P.; Trower, W.P. E-mail: trower@naxs.net; Tyurin, S.A.; Vetrov, A.A.; Yailijan, V.R.; Zayarny, D.A

    2004-10-01

    Here we describe a racetrack microtron that provides electron beams at 12 energies from 4.85 to 34.2 MeV with {approx}150 pC/bunch in {approx}5 ps bunches having {approx}10 mm mrad normalized transverse emittance. Our compact, inexpensive accelerator in addition to its external electron beams can generate electromagnetic radiation from {approx}3 mm to {approx}0.3 nm by a variety of mechanisms.

  6. Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode

    Directory of Open Access Journals (Sweden)

    R. Huang

    2015-01-01

    Full Text Available We report on measurements and analysis of a field-emitted electron current in the very-high-frequency (VHF gun, a room temperature rf gun operating at high field and continuous wave (CW mode at the Lawrence Berkeley National Laboratory (LBNL. The VHF gun is the core of the Advanced Photo-injector Experiment (APEX at LBNL, geared toward the development of an injector for driving the next generation of high average power x-ray free electron lasers. High accelerating fields at the cathode are necessary for the high-brightness performance of an electron gun. When coupled with CW operation, such fields can generate a significant amount of field-emitted electrons that can be transported downstream the accelerator forming the so-called “dark current.” Elevated levels of a dark current can cause radiation damage, increase the heat load in the downstream cryogenic systems, and ultimately limit the overall performance and reliability of the facility. We performed systematic measurements that allowed us to characterize the field emission from the VHF gun, determine the location of the main emitters, and define an effective strategy to reduce and control the level of dark current at APEX. Furthermore, the energy spectra of isolated sources have been measured. A simple model for energy data analysis was developed that allows one to extract information on the emitter from a single energy distribution measurement.

  7. High Brightness, High Average Current Injector Development at Cornell

    CERN Document Server

    Sinclair, C K

    2005-01-01

    Cornell University is constructing a 100 mA average current, high brightness electron injector for a planned Energy Recovery Linac (ERL) hard X-ray synchrotron radiation source. This injector will employ a very high voltage DC gun with a negative electron affinity photoemission cathode. Relatively long duration electron pulses from the photocathode will be drift bunched, and accelerated to 5-15 MeV with five two-cell, 1300 MHz superconducting cavities. The total beam power will be limited to 575 kW by the DC and RF power sources. A genetic algorithm based computational optimization of this injector has resulted in simulated rms normalized emittances of 0.1 mm-mrad at 80 pC/bunch, and 0.7 mm-mrad at 1 nC/bunch. The many technical issues and their design solutions will be discussed. Construction of the gun and the SRF cavities is well underway. The schedule for completion, and the planned measurements, will be presented.

  8. A Compact High-Brightness Heavy-Ion Injector

    CERN Document Server

    Westenskow, Glen; Grote, D P; Halaxa, Erni; Kwan, Joe W

    2005-01-01

    To provide compact high-brightness heavy-ion beams for Heavy Ion Fusion (HIF) accelerators, we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. In an 80-kV 20-microsecond experiment, the RF plasma source has produced up to 5 mA of Ar+ in a single beamlet. An extraction current density of 100 mA/cm2 was achieved, and the thermal temperature of the ions was below 1 eV. More than 90% of the ions were in the Ar+ state, and the energy spread from charge exchange was found to be small. We have tested at full voltage gradient the first 4 gaps of a 61-beamlet injector design. Einzel lens were used to focus the beamlets while reducing the beamlet to beamlet space charge interaction. We will report on a converging 119 multi-beamlet source. Although the source has the same optics as a full 1.6 MV injector system, the test will be carried out at 400 kV due to the test stand HV limit. We will measure the beam’s emittance after the beamlets are merged and have bee...

  9. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1991-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high power laser pulses synchronized to the electron beam, suitable for studies of new methods of high gradient acceleration and state of the art free electron lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 to 100 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps Nd:YAG laser and a 100 mJ, 10 ps CO{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various acceleration schemes, Free-Electron Laser experiments and a program on the development of high brightness electron beams. The AFT's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the High power laser will begin operation this year. 28 refs., 4 figs.

  10. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics

    1992-09-01

    The Accelerator Test Facility (ATF) at BNL is a users` facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF`s experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  11. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1992-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  12. The free-electron laser FLASH

    Institute of Scientific and Technical Information of China (English)

    Siegfried Schreiber; Bart Faatz

    2015-01-01

    FLASH at DESY, Hamburg, Germany is the first free-electron laser(FEL) operating in the extreme ultraviolet(EUV)and soft x-ray wavelength range. FLASH is a user facility providing femtosecond short pulses with an unprecedented peak and average brilliance, opening new scientific opportunities in many disciplines. The first call for user experiments has been launched in 2005. The FLASH linear accelerator is based on TESLA superconducting technology, providing several thousands of photon pulses per second to user experiments. Probing femtosecond-scale dynamics in atomic and molecular reactions using, for instance, a combination of x-ray and optical pulses in a pump and probe arrangement,as well as single-shot diffraction imaging of biological objects and molecules, are typical experiments performed at the facility. We give an overview of the FLASH facility, and describe the basic principles of the accelerator. Recently,FLASH has been extended by a second undulator beamline(FLASH2) operated in parallel to the first beamline, extending the capacity of the facility by a factor of two.

  13. Free electron laser and superconductivity

    CERN Document Server

    Iwata, A

    2003-01-01

    The lasing of the first free-electron laser (FEL) in the world was successfully carried out in 1977, so the history of FELs as a light source is not so long. But FELs are now utilized for research in many scientific and engineering fields owing to such characteristics as tunability of the wavelength, and short pulse and high peak power, which is difficult utilizing a common light source. Research for industrial applications has also been carried out in some fields, such as life sciences, semiconductors, nano-scale measurement, and others. The task for the industrial use of FEL is the realization of high energy efficiency and high optical power. As a means of promoting realization, the combining of an FEL and superconducting linac is now under development in order to overcome the thermal limitations of normal-conducting linacs. Further, since tuning the wavelength is carried out by changing the magnetic density of the undulator, which is now induced by moving part of the stack of permanent magnets, there is un...

  14. VELOCITY BUNCHING OF HIGH-BRIGHTNESS ELECTRON BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S G; Musumeci, P; Rosenzweig, J B; Brown, W J; England, R J; Ferrario, M; Jacob, J S; Thompson, M C; Travish, G; Tremaine, A M; Yoder, R

    2004-10-15

    Velocity bunching has been recently proposed as a tool for compressing electron beam pulses in modern high brightness photoinjector sources. This tool is familiar from earlier schemes implemented for bunching dc electron sources, but presents peculiar challenges when applied to high current, low emittance beams from photoinjectors. The main difficulty foreseen is control of emittance oscillations in the beam in this scheme, which can be naturally considered as an extension of the emittance compensation process at moderate energies. This paper presents two scenarios in which velocity bunching, combined with emittance control, is to play a role in nascent projects. The first is termed ballistic bunching, where the changing of relative particle velocities and positions occur in distinct regions, a short high gradient linac, and a drift length. This scenario is discussed in the context of the proposed ORION photoinjector. Simulations are used to explore the relationship between the degree of bunching, and the emittance compensation process. Experimental measurements performed at the UCLA Neptune Laboratory of the surprisingly robust bunching process, as well as accompanying deleterious transverse effects, are presented. An unanticipated mechanism for emittance growth in bends for highly momentum chirped beam was identified and studied in these experiments. The second scenario may be designated as phase space rotation, and corresponds closely to the recent proposal of Ferrario and Serafini. Its implementation for the compression of the electron beam pulse length in the PLEIADES inverse Compton scattering (ICS) experiment at LLNL is discussed. It is shown in simulations that optimum compression may be obtained by manipulation of the phases in low gradient traveling wave accelerator sections. Measurements of the bunching and emittance control achieved in such an implementation at PLEIADES, as well as aspects of the use of velocity-bunched beam directly in ICS experiments

  15. Velocity bunching of high-brightness electron beams

    Directory of Open Access Journals (Sweden)

    S. G. Anderson

    2005-01-01

    Full Text Available Velocity bunching has been recently proposed as a tool for compressing electron beam pulses in modern high brightness photoinjector sources. This tool is familiar from earlier schemes implemented for bunching dc electron sources, but presents peculiar challenges when applied to high current, low emittance beams from photoinjectors. The main difficulty foreseen is control of emittance oscillations in the beam in this scheme, which can be naturally considered as an extension of the emittance compensation process at moderate energies. This paper presents two scenarios in which velocity bunching, combined with emittance control, is to play a role in nascent projects. The first is termed ballistic bunching, where the changing of relative particle velocities and positions occur in distinct regions, a short high gradient linac, and a drift length. This scenario is discussed in the context of the proposed ORION photoinjector. Simulations are used to explore the relationship between the degree of bunching, and the emittance compensation process. Experimental measurements performed at the UCLA Neptune Laboratory of the surprisingly robust bunching process, as well as accompanying deleterious transverse effects, are presented. An unanticipated mechanism for emittance growth in bends for highly momentum chirped beam was identified and studied in these experiments. The second scenario may be designated as phase space rotation, and corresponds closely to the recent proposal of Ferrario and Serafini. Its implementation for the compression of the electron beam pulse length in the PLEIADES inverse Compton scattering (ICS experiment at LLNL is discussed. It is shown in simulations that optimum compression may be obtained by manipulation of the phases in low gradient traveling wave accelerator sections. Measurements of the bunching and emittance control achieved in such an implementation at PLEIADES, as well as aspects of the use of velocity-bunched beam directly

  16. Beam emittance investigation in high brightness injector using different driver laser profiles

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Beam emittance plays an important role in any accelerator, and it is a main parameter to judge the performance of an accelerator. Emittance optimization is an indispensable part in conditioning and operation of the facility. For a laser-driven high brightness injector, different time structure of the laser pulse has different effects on transverse emittance. In order to compare Gaussian and flat-top laser pulse, systematic simulations of 500 pC have been done. From the simulation results, one can see that flat-top pulse laser will yield smaller minimal transverse beam size and transverse beam emittance than Gaussian pulse laser.

  17. Component technologies for a recirculating linac free-electron laser

    Science.gov (United States)

    Litvinenko, Vladimir N.; Madey, John M. J.; Vinokurov, Nikolai A.

    1994-05-01

    The key component technologies required for a high average power free-electron laser (FEL) are described. Some basic aspects of approaches for high average power (scalable to megawatt level) accelerators and FELs are presented. A short description of the Novosibirsk 100 kW average power near infrared (IR) FEL driven by a race-track microtron-recuperator is given. The current status and plans for this facility are provided by Institute of Nuclear Physics (Novosibirsk).

  18. Development of components for the high brightness laser

    Science.gov (United States)

    Garmire, E.

    1980-10-01

    In 1979 DBR lasers were fabricated and their properties studied. Further investigations were undertaken of the beam expander, to determine its potential for the high brightness laser. From this data it was determined that a design change for the high brightness laser is required. This design change is described. In addition, measurements were made on laser amplification to compare this method of achieving higher power compared to the coupled diode arrays. Finally, as a spin-off of this research, a new design for a single mode laser was discovered, using the active/passive laser, a configuration which was fabricated as a first step toward fabrication of DBR lasers. Each of these research efforts are described in this report. Monolithic integration of the necessary components on one substrate for the high brightness laser has been hindered by problems in material and fabrication uniformity. This will be described, and projections for future development will be outlined.

  19. Laser ion source for high brightness heavy ion beam

    Science.gov (United States)

    Okamura, M.

    2016-09-01

    A laser ion source is known as a high current high charge state heavy ion source. However we place great emphasis on the capability to realize a high brightness ion source. A laser ion source has a pinpoint small volume where materials are ionized and can achieve quite uniform low temperature ion beam. Those features may enable us to realize very small emittance beams. In 2014, a low charge state high brightness laser ion source was successfully commissioned in Brookhaven National Laboratory. Now most of all the solid based heavy ions are being provided from the laser ion source for regular operation.

  20. Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Higley, Daniel J., E-mail: dhigley@stanford.edu; Yuan, Edwin [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Hirsch, Konstantin; Dakovski, Georgi L.; Jal, Emmanuelle; Lutman, Alberto A.; Coslovich, Giacomo; Hart, Philip; Hoffmann, Matthias C.; Mitra, Ankush; Moeller, Stefan; Ohldag, Hendrik; Seaberg, Matthew; Stöhr, Joachim; Nuhn, Heinz-Dieter; Reid, Alex H.; Dürr, Hermann A.; Schlotter, William F. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Liu, Tianmin; MacArthur, James P. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); and others

    2016-03-15

    X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L{sub 3,2}-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature.

  1. An infrared free-electron laser for the Chemical Dynamics Research Laboratory. Design report

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, D. [comp.

    1992-04-01

    This document describes a free-electron laser (FEL) proposed as part of the Chemical Dynamics Research Laboratory (CDRL), a user facility that also incorporates several advanced lasers of conventional design and two beamlines for the ALS. The FEL itself addresses the needs of the chemical sciences community for a high-brightness, tunable source covering a broad region of the infrared spectrum -- from 3 to 50 {mu}m. All of these sources, together with a variety of sophisticated experimental stations, will be housed in a new building to be located adjacent to the ALS. The radiation sources can be synchronized to permit powerful two-color, pump-probe experiments that will further our fundamental understanding of chemical dynamics at the molecular level, especially those aspects relevant to practical issues in combustion chemistry. The technical approach adopted in this design makes use of superconducting radiofrequency (SCRF) accelerating structures. The primary motivation for adopting this approach was to meet the user requirement for wavelength stability equal to one part in 10{sup 4}. Previous studies concluded that a wavelength stability of only one part in 10{sup 3} could be achieved with currently available room-temperature technology. In addition, the superconducting design operates in a continuous-wave (cw) mode and hence offers considerably higher average optical output power. It also allows for various pulse-gating configurations that will permit simultaneous multiuser operations. A summary of the comparative performance attainable with room-temperature and superconducting designs is given. The FEL described in this report provides a continuous train of 30-ps micropulses, with 100{mu}J of optical energy per micropulse, at a repetition rate of 6.1 MHz. The device can also deliver pulses at a cw repetition rate of 12.2 MHz, with a peak power of 50 {mu}J per micropulse. 70 ref.

  2. An infrared free-electron laser for the Chemical Dynamics Research Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, D. (comp.)

    1992-04-01

    This document describes a free-electron laser (FEL) proposed as part of the Chemical Dynamics Research Laboratory (CDRL), a user facility that also incorporates several advanced lasers of conventional design and two beamlines for the ALS. The FEL itself addresses the needs of the chemical sciences community for a high-brightness, tunable source covering a broad region of the infrared spectrum -- from 3 to 50 {mu}m. All of these sources, together with a variety of sophisticated experimental stations, will be housed in a new building to be located adjacent to the ALS. The radiation sources can be synchronized to permit powerful two-color, pump-probe experiments that will further our fundamental understanding of chemical dynamics at the molecular level, especially those aspects relevant to practical issues in combustion chemistry. The technical approach adopted in this design makes use of superconducting radiofrequency (SCRF) accelerating structures. The primary motivation for adopting this approach was to meet the user requirement for wavelength stability equal to one part in 10{sup 4}. Previous studies concluded that a wavelength stability of only one part in 10{sup 3} could be achieved with currently available room-temperature technology. In addition, the superconducting design operates in a continuous-wave (cw) mode and hence offers considerably higher average optical output power. It also allows for various pulse-gating configurations that will permit simultaneous multiuser operations. A summary of the comparative performance attainable with room-temperature and superconducting designs is given. The FEL described in this report provides a continuous train of 30-ps micropulses, with 100{mu}J of optical energy per micropulse, at a repetition rate of 6.1 MHz. The device can also deliver pulses at a cw repetition rate of 12.2 MHz, with a peak power of 50 {mu}J per micropulse. 70 ref.

  3. Free electron laser for gamma-gamma collider at TESLA

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2000-01-01

    The present paper contains the results of optimization of the free electron laser for the gamma-gamma collider at TESLA. A superconducting linear accelerator, similar to the TESLA test facility (TTF) accelerator, produces a driving electron beam for the FEL. The MOPA FEL scheme is studied when the radiation from a master oscillator is amplified in the FEL amplifier with tapered undulator. The FEL produces the radiation of TW level with a wavelength of 1 mu m. Optimization of the FEL amplifier is performed with three-dimensional, time-dependent simulation code FAST.

  4. Aerosol Imaging with a Soft X-ray Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Bogan, Michael J.; /SLAC /LLNL, Livermore; Boutet, Sebastien; /SLAC; Chapman, Henry N.; /DESY /Hamburg U.; Marchesini, Stefano; /LBL, Berkeley; Barty, Anton; Benner, W.Henry /LLNL, Livermore; Rohner, Urs; /LLNL, Livermore /TOFWERK AG; Frank, Matthias; Hau-Riege, Stefan P.; /LLNL, Livermore; Bajt, Sasa; /DESY; Woods, Bruce; /LLNL, Livermore; Seibert, M.M.; Iwan, Bianca; Timneanu, Nicusor; Hajdu, Janos; /Uppsala U.; Schulz, Joachim; /DESY

    2011-08-22

    Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.

  5. Field Emitter Arrays for a Free Electron Laser Application

    CERN Document Server

    Shing-Bruce-Li, Kevin; Ganter, Romain; Gobrecht, Jens; Raguin, Jean Yves; Rivkin, Leonid; Wrulich, Albin F

    2004-01-01

    The development of a new electron gun with the lowest possible emittance would help reducing the total length and cost of a free electron laser. Field emitter arrays (FEAs) are an attractive technology for electron sources of ultra high brightness. Indeed, several thousands of microscopic tips can be deposited on a 1 mm diameter area. Electrons are then extracted by applying voltage to a first grid layer close to the tip apexes, the so called gate layer, and focused by a second grid layer one micrometer above the tips. The typical aperture diameter of the gate and the focusing layer is in the range of one micrometer. One challenge for such cathodes is to produce peak currents in the ampere range since the usual applications of FEAs require less than milliampere. Encouraging peak current performances have been obtained by applying voltage pulses at low frequency between gate and tips. In this paper we report on different tip materials available on the market: diamond FEAs from Extreme Devices Inc., ZrC single ...

  6. Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

    Science.gov (United States)

    Scoby, Cheyne Matthew

    This thesis explores the use of ultrashort bunches generated by a radiofrequency electron photoinjector driven by a femtosecond laser. Rf photoinjector technology has been developed to generate ultra high brightness beams for advanced accelerators and to drive advanced light source applications. The extremely good quality of the beams generated by this source has played a key role in the development of 4th generation light sources such as the Linac Coherent Light Source, thus opening the way to studies of materials science and biological systems with high temporal and spatial resolution. At the Pegasus Photoinjector Lab, we have developed the application of a BNL/SLAC/UCLA 1.6-cell rf photoinjector as a tool for ultrafast science in its own right. It is the aim of this work to explore the generation of ultrashort electron bunches, give descriptions of the novel ultrafast diagnostics developed to be able to characterize the electron bunch and synchronize it with a pump laser, and share some of the scientific results that were obtained with this technology at the UCLA Pegasus laboratory. This dissertation explains the requirements of the drive laser source and describes the principles of rf photoinjector design and operation necessary to produce electron bunches with an rms longitudinal length < 100 femtoseconds containing 107 - 108 electrons per bunch. In this condition, when the laser intensity is sufficiently high, multiphoton photoemission is demonstrated to be more efficient in terms of charge yield than single photon photoemission. When a short laser pulse hits the cathode the resulting beam dynamics are dominated by a strong space charge driven longitudinal expansion which leads to the creation of a nearly ideal uniformly filled ellipsoidal distribution. These beam distributions are characterized by linear space charge forces and hence by high peak brightness and small transverse emittances. This regime of operation of the RF photoinjector is also termed the

  7. Production of quasi ellipsoidal laser pulses for next generation high brightness photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Rublack, T., E-mail: Tino.Rublack@desy.de [DESY, Zeuthen (Germany); Good, J.; Khojoyan, M.; Krasilnikov, M.; Stephan, F. [DESY, Zeuthen (Germany); Hartl, I.; Schreiber, S. [DESY, Hamburg (Germany); Andrianov, A.; Gacheva, E.; Khazanov, E.; Mironov, S.; Potemkin, A.; Zelenogorskii, V.V. [IAP/RAS, Nizhny Novgorod (Russian Federation); Syresin, E. [JINR, Dubna (Russian Federation)

    2016-09-01

    The use of high brightness electron beams in Free Electron Laser (FEL) applications is of increasing importance. One of the most promising methods to generate such beams is the usage of shaped photocathode laser pulses. It has already demonstrated that temporal and transverse flat-top laser pulses can produce very low emittance beams [1]. Nevertheless, based on beam simulations further improvements can be achieved using quasi-ellipsoidal laser pulses, e.g. 30% reduction in transverse projected emittance at 1 nC bunch charge. In a collaboration between DESY, the Institute of Applied Physics of the Russian Academy of Science (IAP RAS) in Nizhny Novgorod and the Joint Institute of Nuclear Research (JINR) in Dubna such a laser system capable of producing trains of laser pulses with a quasi-ellipsoidal distribution, has been developed. The prototype of the system was installed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) and is currently in the commissioning phase. In the following, the laser system will be introduced, the procedure of pulse shaping will be described and the last experimental results will be shown.

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

    Energy Technology Data Exchange (ETDEWEB)

    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; Stohr, Joachim; Stupakov, Gennady; White, Bill; Xiang, Dao

    2009-06-08

    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

  9. Cesium telluride cathodes for the next generation of high-average current high-brightness photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Filippetto, D., E-mail: dfilippetto@lbl.gov; Qian, H.; Sannibale, F. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States)

    2015-07-27

    We report on the performances of a Cs{sub 2}Te photocathode under extreme conditions of high peak time-dependent accelerating fields, continuous wave operations, and MHz pulse extraction with up to 0.3 mA average current. The measurements, performed in a normal conducting cavity, show extended lifetime and robustness, elucidate the main mechanisms for cathode degradation, and set the required system vacuum performance for compatibility with the operations of a high average power X-ray free electron laser user facility, opening the doors to the next generation of MHz-scale ultrafast scientific instruments.

  10. Highly Bright White Organic Light-Emitting Diode

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ A highly bright white organic light-emitting diode (OLED) was realized by using a highly bright blue emitting layer, 1,7-diphenyl-4-biphenyl-3,5-dimethyl-l,7-dihydrodipyrazolo[3,4-b;4',3'-e]pyridine (PAP-Ph), together with a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM)-doped Alq [tris(8-hydroxyquinolinato) aluminum (Ⅲ)] layer to provide the blue, red and green emission for color mixing. With appropriate thickness control, the white-light OLED has a performance that reaches 24700 cd/m2 at 15 V, 1.93 lm/W at 6.5 V, and >300 cd/m2 at 7.7 mA/em2. The Commission Internationale de l'Eclairage (CIE) coordinates of the emitted light vary in a very small range, from (0.35, 0.34) to (0.34, 0.35), when forward voltages change from 6 to 12 V.

  11. Highly Bright White Organic Light-Emitting Diode

    Institute of Scientific and Technical Information of China (English)

    KO; C.; W.

    2001-01-01

    A highly bright white organic light-emitting diode (OLED) was realized by using a highly bright blue emitting layer, 1,7-diphenyl-4-biphenyl-3,5-dimethyl-l,7-dihydrodipyrazolo[3,4-b;4',3'-e]pyridine (PAP-Ph), together with a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM)-doped Alq [tris(8-hydroxyquinolinato) aluminum (Ⅲ)] layer to provide the blue, red and green emission for color mixing. With appropriate thickness control, the white-light OLED has a performance that reaches 24700 cd/m2 at 15 V, 1.93 lm/W at 6.5 V, and >300 cd/m2 at 7.7 mA/em2. The Commission Internationale de l'Eclairage (CIE) coordinates of the emitted light vary in a very small range, from (0.35, 0.34) to (0.34, 0.35), when forward voltages change from 6 to 12 V.  ……

  12. High-brightness, fiber-coupled pump modules in fiber laser applications

    Science.gov (United States)

    Hemenway, Marty; Urbanek, Wolfram; Hoener, Kylan; Kennedy, Keith W.; Bao, Ling; Dawson, David; Cragerud, Emily S.; Balsley, David; Burkholder, Gary; Reynolds, Mitch; Price, Kirk; Haden, Jim; Kanskar, Manoj; Kliner, Dahv A.

    2014-03-01

    High-power, high-brightness, fiber-coupled pump modules enable high-performance industrial fiber lasers with simple system architectures, multi-kW output powers, excellent beam quality, unsurpassed reliability, and low initial and operating costs. We report commercially available (element™), single-emitter-based, 9xx nm pump sources with powers up to 130 W in a 105 μm fiber and 250 W in a 200 μm fiber. This combination of high power and high brightness translates into improved fiber laser performance, e.g., simultaneously achieving high nonlinear thresholds and excellent beam quality at kW power levels. Wavelength-stabilized, 976 nm versions of these pumps are available for applications requiring minimization of the gain-fiber length (e.g., generation of high-peak-power pulses). Recent prototypes have achieved output powers up to 300 W in a 200 μm fiber. Extensive environmental and life testing at both the chip and module level under accelerated and real-world operating conditions have demonstrated extremely high reliability, with innovative designs having eliminated package-induced-failure mechanisms. Finally, we report integrated Pump Modules that provide conveniently formatted for fiber-laser pumping or direct-diode applications; these 19" rack-mountable, 2U units combine the outputs of up to 14 elements™ using fused-fiber combiners, and they include high-efficiency diode drivers and safety sensors.

  13. Free-electron laser emission architecture impact on EUV lithography

    Science.gov (United States)

    Hosler, Erik R.; Wood, Obert R.; Barletta, William A.

    2017-03-01

    Laser-produced plasma (LPP) EUV sources have demonstrated approximately 125 W at customer sites, establishing confidence in EUV lithography as a viable manufacturing technology. However, beyond the 7 nm technology node existing scanner/source technology must enable higher-NA imaging systems (requiring increased resist dose and providing half-field exposures) and/or EUV multi-patterning (requiring increased wafer throughput proportional to the number of exposure passes. Both development paths will require a substantial increase in EUV source power to maintain the economic viability of the technology, creating an opportunity for free-electron laser (FEL) EUV sources. FEL-based EUV sources offer an economic, high-power/single-source alternative to LPP EUV sources. Should free-electron lasers become the preferred next generation EUV source, the choice of FEL emission architecture will greatly affect its operational stability and overall capability. A near-term industrialized FEL is expected to utilize one of the following three existing emission architectures: (1) selfamplified spontaneous emission (SASE), (2) regenerative amplification (RAFEL), or (3) self-seeding (SS-FEL). Model accelerator parameters are put forward to evaluate the impact of emission architecture on FEL output. Then, variations in the parameter space are applied to assess the potential impact to lithography operations, thereby establishing component sensitivity. The operating range of various accelerator components is discussed based on current accelerator performance demonstrated at various scientific user facilities. Finally, comparison of the performance between the model accelerator parameters and the variation in parameter space provides a means to evaluate the potential emission architectures. A scorecard is presented to facilitate this evaluation and provide a framework for future FEL design and enablement for EUV lithography applications.

  14. Chaos in free electron laser oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Bruni, C. [Univ Paris 11, LAL, UMR 8607, F-91898 Orsay, (France); Bachelard, R.; Couprie, M.E. [Synchrotron SOLEIL, F-91192 Gif Sur Yvette, (France); Garzella, D. [CEA DSM DRECAM SPAM, F-91191 Gif Sur Yvette, (France); Orlandi, G.L. [CR Frascati FIM FISACC, ENEA, I-00044 Frascati, (Italy)

    2009-07-01

    The chaotic nature of a storage-ring free electron laser (FEL) is investigated. The derivation of a low embedding dimension for the dynamics allows the low-dimensionality of this complex system to be observed, whereas its unpredictability is demonstrated, in some ranges of parameters, by a positive Lyapounov exponent. The route to chaos is then explored by tuning a single control parameter, and a period-doubling cascade is evidenced, as well as intermittence. (authors)

  15. High Brightness Plasmon-Enhanced Nanostructured Gold Photoemitters

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; Joly, Alan G.; Kong, Lingmei; El-Khoury, Patrick Z.; Hess, Wayne P.

    2014-12-30

    Plasmonic nanohole arrays are fabricated in gold thin films by focused ion beam (FIB) lithography. Subsequent heat treatment creates sub 100 nm nanometric structures including tips, rods and flakes, all localized in the nanohole array region. The combined nanohole array and nanostructured surface comprise an efficient photoemitter. High brightness photoemission is observed from this construct using photoemission electron microscopy (PEEM), following 780 nm femtosecond (fs) laser irradiation. By comparing our observables to results of finite difference time domain (FDTD) calculations, we demonstrate that photoemission from the sub-100 nm structures is enhanced in the region of propagating surface plasmons launched from the nanohole arrays. Additionally, by tuning hole diameter and separation in the nanohole array, the photoemission intensity of nanostructured photoemitters can be controlled. We observe a photoemission enhancement of over 108, relative to photoemission from the flat region of the gold substrate at laser intensities well below the ablation threshold.

  16. ROLE OF DIAMOND SECONDARY EMITTERS IN HIGH BRIGHTNESS ELECTRON SOURCES.

    Energy Technology Data Exchange (ETDEWEB)

    RAO, T.; BEN-ZVI, I.; BURRILL, A.; CHANG, X.; GRIMES, J.; RANK, J.; SEGALOV, Z.; SMEDLEY, J.

    2005-09-20

    In this paper we explore the possibility of using diamond secondary emitter in a high average current electron injector to amplify the current from the photocathode and to isolate the cathode and the injector from each other to increase the life time of the cathode and preserve the performance of the injector. Secondary electron yield of 225 and current density of 0.8 a/cm{sup 2} have been measured in the transmission mode from type 2 a natural diamond. Although the diamond will be heated during normal operation in the injector, calculations indicate that by cryogenically cooling the diamond, the temperature gradient along the diamond can be maintained within the acceptable range. The electron energy and temporal distributions are expected to be narrow from this device resulting in high brightness beams. Plans are underway to measure the SEY in emission mode, fabricate photocathode-diamond capsule and test diamond and capsule in superconducting RF injector.

  17. Ultra-high resolution and high-brightness AMOLED

    Science.gov (United States)

    Wacyk, Ihor; Ghosh, Amal; Prache, Olivier; Draper, Russ; Fellowes, Dave

    2012-06-01

    As part of its continuing effort to improve both the resolution and optical performance of AMOLED microdisplays, eMagin has recently developed an SXGA (1280×3×1024) microdisplay under a US Army RDECOM CERDEC NVESD contract that combines the world's smallest OLED pixel pitch with an ultra-high brightness green OLED emitter. This development is aimed at next-generation HMD systems with "see-through" and daylight imaging requirements. The OLED pixel array is built on a 0.18-micron CMOS backplane and contains over 4 million individually addressable pixels with a pixel pitch of 2.7 × 8.1 microns, resulting in an active area of 0.52 inches diagonal. Using both spatial and temporal enhancement, the display can provide over 10-bits of gray-level control for high dynamic range applications. The new pixel design also enables the future implementation of a full-color QSXGA (2560 × RGB × 2048) microdisplay in an active area of only 1.05 inch diagonal. A low-power serialized low-voltage-differential-signaling (LVDS) interface is integrated into the display for use as a remote video link for tethered systems. The new SXGA backplane has been combined with the high-brightness green OLED device developed by eMagin under an NVESD contract. This OLED device has produced an output brightness of more than 8000fL with all pixels on; lifetime measurements are currently underway and will presented at the meeting. This paper will describe the operational features and first optical and electrical test results of the new SXGA demonstrator microdisplay.

  18. Electron injector for Iranian Infrared Free Electron Laser

    Science.gov (United States)

    Rajabi, A.; Jazini, J.; Fathi, M.; Khosravi, N.; Shokri, B.

    2016-12-01

    The quality of the electron beam for applications like free electron lasers (FELs) has a direct impact on the quality of the laser radiation. The electron injector considered for Iranian Infrared Free Electron Laser (IRIFEL) includes a thermionic RF electron gun plus a bunch compressor as the electron preinjector and a 50 MeV constant gradient traveling wave linac as the main accelerator of the electron injector. In the present work, a thermionic RF gun is designed and matched with an optimized linac to produce a high quality mono-energetic electron beam. The results show that the preinjector is capable of delivering an electron bunch with 1 ps bunch length and 3 mm-mrad emittance to the linac entrance which is desirable for IRIFEL operation. The results also show that by geometrical manipulation and optimization of the linac structure, the pattern of the RF fields in the linac will be more symmetric, which is important in order to produce high stable mono-energetic bunches.

  19. Controlling excitons. Concepts for phosphorescent organic LEDs at high brightness

    Energy Technology Data Exchange (ETDEWEB)

    Reineke, Sebastian

    2009-11-15

    This work focusses on the high brightness performance of phosphorescent organic light-emitting diodes (OLEDs). The use of phosphorescent emitter molecules in OLEDs is essential to realize internal electron-photon conversion efficiencies of 100 %. However, due to their molecular nature, the excited triplet states have orders of magnitude longer time constants compared to their fluorescent counterparts which, in turn, strongly increases the probability of bimolecular annihilation. As a consequence, the efficiencies of phosphorescent OLEDs decline at high brightness - an effect known as efficiency roll-off, for which it has been shown to be dominated by triplet-triplet annihilation (TTA). In this work, TTA of the archetype phosphorescent emitter Ir(ppy){sub 3} is investigated in time-resolved photoluminescence experiments. For the widely used mixed system CBP:Ir(ppy){sub 3}, host-guest TTA - an additional unwanted TTA channel - is experimentally observed at high excitation levels. By using matrix materials with higher triplet energies, this effect is efficiently suppressed, however further studies show that the efficiency roll-off of Ir(ppy)3 is much more pronounced than predicted by a model based on Foerster-type energy transfer, which marks the intrinsic limit for TTA. These results suggest that the emitter molecules show a strong tendency to form aggregates in the mixed film as the origin for enhanced TTA. Transmission electron microscopy images of Ir(ppy){sub 3} doped mixed films give direct proof of emitter aggregates. Based on these results, two concepts are developed that improve the high brightness performance of OLEDs. In a first approach, thin intrinsic matrix interlayers are incorporated in the emission layer leading to a one-dimensional exciton confinement that suppresses exciton migration and, consequently, TTA. The second concept reduces the efficiency roll-off by using an emitter molecule with slightly different chemical structure, i.e. Ir(ppy){sub 2

  20. Quantum aspects of the free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Gaiba, R.

    2007-03-15

    We study the role of Quantum Mechanics in the physics of Free Electron Lasers. While the Free Electron Laser (FEL) is usually treated as a classical device, we review the advantages of a quantum formulation of the FEL. We then show the existence of a regime of operation of the FEL that can only be described using Quantum Mechanics: if the dimensionless quantum parameter anti {rho} is smaller than 1, then in the 1-dimensional approximation the Hamiltonian that describes the FEL becomes equivalent to the Hamiltonian of a two-level system coupled to a radiation field. We give analytical and numerical solutions for the photon statistics of a Free Electron Laser operating in the quantum regime under various approximations. Since in the quantum regime the momentum of the electrons is discrete, we give a description of the electrons in phase space by introducing the Discrete Wigner Function. We then drop the assumption of a mono-energetic electron beam and describe the general case of a initial electron energy spread G({gamma}). Numerical analysis shows that the FEL quantum regime is observed only when the width of the initial momentum distribution is smaller than the momentum of the emitted photons. Both the analytical results in the linear approximation and the numerical simulations show that only the electrons close to a certain resonant energy start to emit photons. This generates the so-called Hole-burning effect in the electrons energy distribution, as it can be seen in the simulations we provide. Finally, we present a brief discussion about a fundamental uncertainty relation that ties the electron energy spread and the electron bunching. (orig.)

  1. The FERMI free-electron lasers.

    Science.gov (United States)

    Allaria, E; Badano, L; Bassanese, S; Capotondi, F; Castronovo, D; Cinquegrana, P; Danailov, M B; D'Auria, G; Demidovich, A; De Monte, R; De Ninno, G; Di Mitri, S; Diviacco, B; Fawley, W M; Ferianis, M; Ferrari, E; Gaio, G; Gauthier, D; Giannessi, L; Iazzourene, F; Kurdi, G; Mahne, N; Nikolov, I; Parmigiani, F; Penco, G; Raimondi, L; Rebernik, P; Rossi, F; Roussel, E; Scafuri, C; Serpico, C; Sigalotti, P; Spezzani, C; Svandrlik, M; Svetina, C; Trovó, M; Veronese, M; Zangrando, D; Zangrando, M

    2015-05-01

    FERMI is a seeded free-electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy, and is now in user operation with its first FEL line, FEL-1, covering the wavelength range between 100 and 20 nm. The second FEL line, FEL-2, a high-gain harmonic generation double-stage cascade covering the wavelength range 20-4 nm, has also completed commissioning and the first user call has been recently opened. An overview of the typical operating modes of the facility is presented.

  2. Progress toward the Wisconsin Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    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

    2011-03-01

    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.

  3. Free Electron Lasers using `Beam by Design'

    CERN Document Server

    Henderson, J R; McNeil, B W J

    2015-01-01

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

  4. Kinetic theory of free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hafizi, B. [Naval Research Lab., Washington, DC (United States); Roberson, C.W. [Office of Naval Research, Arlington, VA (United States)

    1995-12-31

    We have developed a relativistic kinetic theory of free electron lasers (FELs). The growth rate, efficiency, filling factor and radius of curvature of the radiation wave fronts are determined. We have used the theory to examine the effects of beam compression on growth rate. The theory has been extended to include self field effects on FEL operation. These effects are particularly important in compact, low voltage FELs. The surprising result is that the self field contribution to the beam quality is opposite to the emittance contribution. Hence self fields can improve beam quality, particularly in compact, low voltage FELs.

  5. Focused ion beams using a high-brightness plasma source

    Science.gov (United States)

    Guharay, Samar

    2002-10-01

    High-brightness ion beams, with low energy spread, have merits for many new applications in microelectronics, materials science, and biology. Negative ions are especially attractive for the applications that involve beam-solid interactions. When negative ions strike a surface, especially an electrically isolated surface, the surface charging voltage is limited to few volts [1]. This property can be effectively utilized to circumvent problems due to surface charging, such as device damage and beam defocusing. A compact plasma source, with the capability to deliver either positive or negative ion beams, has been developed. H- beams from this pulsed source showed brightness within an order of magnitude of the value for beams from liquid-metal ion sources. The beam angular intensity is > 40 mAsr-1 and the corresponding energy spread is 1 Acm-2 and a spot size of 100 nm. Such characteristics of focused beam parameters, using a dc source, will immediately open up a large area of new applications. [1] P. N. Guzdar, A. S. Sharma, S. K. Guharay, "Charging of substrates irradiated by particle beams" Appl. Phys. Lett. 71, 3302 (1997). [2] S. K. Guharay, E. Sokolovsky, J. Orloff, "Characteristics of ion beams from a Penning source for focused ion beam applications" J. Vac. Sci Technol. B17, 2779 (1999).

  6. Low Cost Lithography Tool for High Brightness LED Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Hawryluk; Emily True

    2012-06-30

    The objective of this activity was to address the need for improved manufacturing tools for LEDs. Improvements include lower cost (both capital equipment cost reductions and cost-ofownership reductions), better automation and better yields. To meet the DOE objective of $1- 2/kilolumen, it will be necessary to develop these highly automated manufacturing tools. Lithography is used extensively in the fabrication of high-brightness LEDs, but the tools used to date are not scalable to high-volume manufacturing. This activity addressed the LED lithography process. During R&D and low volume manufacturing, most LED companies use contact-printers. However, several industries have shown that these printers are incompatible with high volume manufacturing and the LED industry needs to evolve to projection steppers. The need for projection lithography tools for LED manufacturing is identified in the Solid State Lighting Manufacturing Roadmap Draft, June 2009. The Roadmap states that Projection tools are needed by 2011. This work will modify a stepper, originally designed for semiconductor manufacturing, for use in LED manufacturing. This work addresses improvements to yield, material handling, automation and throughput for LED manufacturing while reducing the capital equipment cost.

  7. High current racetrack microtron as a free electron laser driver

    Science.gov (United States)

    Kurakin, V. G.

    1994-03-01

    A racetrack microtron combines the best features of a linac and a classical microtron. It might serve as a basis for free electron lasers to make these promising devices more compact and relatively cheap and thus available for many laboratories. At the same time it is known that stable acceleration in a racetrack is broken up at high intensity by automodulation of the beam current. It is shown in this paper that such modulation originates from positive feedback arising at some frequencies between the system rf cavity and the electron beam. The beam-cavity interaction equations followed by a stability analysis are presented. A linear approximation is used to derive stability conditions, the latter being represented in an analytical form followed by numerical calculations and a stability diagram. Comparing the results obtained with experimentally measured values shows the validity of the approach used. The physical meaning of observed intensity modulation as well as some measures of their suppression are discussed.

  8. XUV free-electron laser-based projection lithography systems

    Energy Technology Data Exchange (ETDEWEB)

    Newnam, B.E.

    1990-01-01

    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.

  9. Airborne Tactical Free-Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, Roy; Neil, George

    2007-02-01

    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.

  10. Holographic free-electron light source

    Science.gov (United States)

    Li, Guanhai; Clarke, Brendan P.; So, Jin-Kyu; MacDonald, Kevin F.; Zheludev, Nikolay I.

    2016-12-01

    Recent advances in the physics and technology of light generation via free-electron proximity and impact interactions with nanostructures (gratings, photonic crystals, nano-undulators, metamaterials and antenna arrays) have enabled the development of nanoscale-resolution techniques for such applications as mapping plasmons, studying nanoparticle structural transformations and characterizing luminescent materials (including time-resolved measurements). Here, we introduce a universal approach allowing generation of light with prescribed wavelength, direction, divergence and topological charge via point-excitation of holographic plasmonic metasurfaces. It is illustrated using medium-energy free-electron injection to generate highly-directional visible to near-infrared light beams, at selected wavelengths in prescribed azimuthal and polar directions, with brightness two orders of magnitude higher than that from an unstructured surface, and vortex beams with topological charge up to ten. Such emitters, with micron-scale dimensions and the freedom to fully control radiation parameters, offer novel applications in nano-spectroscopy, nano-chemistry and sensing.

  11. Comparison of short pulse generation schemes for a soft x-ray free electron laser

    Science.gov (United States)

    Martin, I. P. S.; Bartolini, R.

    2011-03-01

    In this paper we study the performance of two complementary short pulse generation schemes as applied to a soft x-ray free electron laser. The first scheme, recently proposed by Saldin et al., makes use of a laser pulse consisting of only a few optical cycles to give an energy chirp to a short section of an electron bunch and tapers the main radiator undulator in order to compensate the chirped region. The second scheme investigated takes a low-charge, high brightness electron bunch and compresses it to ˜1fs in order to operate in the so-called “single-spike” regime. We perform start-to-end simulations of both these schemes, assess the sensitivity of each scheme to realistic jitter sources, and provide a direct comparison of the respective strengths and drawbacks.

  12. Comparison of short pulse generation schemes for a soft x-ray free electron laser

    Directory of Open Access Journals (Sweden)

    I. P. S. Martin

    2011-03-01

    Full Text Available In this paper we study the performance of two complementary short pulse generation schemes as applied to a soft x-ray free electron laser. The first scheme, recently proposed by Saldin et al., makes use of a laser pulse consisting of only a few optical cycles to give an energy chirp to a short section of an electron bunch and tapers the main radiator undulator in order to compensate the chirped region. The second scheme investigated takes a low-charge, high brightness electron bunch and compresses it to ∼1  fs in order to operate in the so-called “single-spike” regime. We perform start-to-end simulations of both these schemes, assess the sensitivity of each scheme to realistic jitter sources, and provide a direct comparison of the respective strengths and drawbacks.

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

    CERN Document Server

    Behrens, Christopher; Xiang, Dao

    2011-01-01

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

  14. Status of the Northrop Grumman Compact Infrared Free-Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Lehrman, I.S.; Krishnaswamy, J.; Hartley, R.A. [Northrop Grumman Advanced Technology & Development Center, Princeton, NJ (United States)] [and others

    1995-12-31

    The Compact Infrared Free Electron Laser (CIRFEL) was built as part of a joint collaboration between the Northrop Grumman Corporation and Princeton University to develop FEL`s for use by researchers in the materials, medical and physical sciences. The CIRFEL was designed to lase in the Mid-IR and Far-IR regimes with picosecond pulses, megawatt level peak powers and an average power of a few watts. The micropulse separation is 7 nsec which allows a number of relaxation phenomenon to be observed. The CIRFEL utilizes an RF photocathode gun to produce high-brightness time synchronized electron bunches. The operational status and experimental results of the CERFEL will be presented.

  15. Modelling elliptically polarised Free Electron Lasers

    CERN Document Server

    Henderson, J R; Freund, H P; McNeil, B W J

    2016-01-01

    A model of a Free Electron Laser operating with an elliptically polarised undulator is presented. The equations describing the FEL interaction, including resonant harmonic radiation fields, are averaged over an undulator period and generate a generalised Bessel function scaling factor, similar to that of planar undulator FEL theory. Comparison between simulations of the averaged model with those of an unaveraged model show very good agreement in the linear regime. Two unexpected results were found. Firstly, an increased coupling to harmonics for elliptical rather than planar polarisarised undulators. Secondly, and thought to be unrelated to the undulator polarisation, a signficantly different evolution between the averaged and unaveraged simulations of the harmonic radiation evolution approaching FEL saturation.

  16. Control of Coherent Synchrotron Radiation and Micro-Bunching Effects During Transport of High Brightness Electron Beams

    CERN Document Server

    Douglas, D R; Hutton, A; Krafft, G A; Li, R; Neil, G R; Roblin, Y; Tennant, C D; Tsai, C -Y

    2014-01-01

    Beam quality preservation during transport of high-brightness electron beams is of general concern in the design of modern accelerators. Methods to manage incoherent synchrotron radiation (ISR) have been in place for decades; as beam brightness has improved coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have emerged as performance limitations. We apply the compensation analysis of diMitri, Cornacchia, and Spampinati - as previously used by Borland - to the design of transport systems for use with low-emittance beams, and find that appropriately configured second order achromats will suppress transverse emittance growth due to CSR and appear to limit uBI gain.

  17. Beam extraction dynamics at the space-charge-limit of the high brightness E-XFEL electron source at DESY-PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ye; Gjonaj, Erion; Weiland, Thomas [TEMF, Technische Universitaet Darmstadt, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

    2015-07-01

    The physics of the photoemission, as one of the key issues for successful operation of linac based free-electron lasers like the European X-ray Free Electron Laser (E-XFEL) and the Free-electron Laser in Hamburg (FLASH), is playing an increasingly important role in the high brightness DESY-PITZ electron source. We study photoemission physics and discuss full three-dimensional numerical modeling of the electron bunch emission. The beam extraction dynamics at the photocathode has been investigated through the 3D fully electromagnetic (EM) Particle-in-Cell (PIC) solver of CST Particle Studio under the assumption of the photoemission source operating at or close to its space charge limit. PIC simulation results have shown good agreements with measurements on total emitted bunch charge for distinct experimental parameters. Further comparisons showed a general failure for the conventional Poisson solver based tracking algorithm to correctly predict the beam dynamics at the space charge limit. It is furthermore found, that fully EM PIC simulations are also consistent with a simple emission model based on the multidimensional Child-Langmuir law.

  18. Free electron lasers for transmission of energy in space

    Science.gov (United States)

    Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

    1981-01-01

    A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

  19. Free electron lasers: Present status and future challenges

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, W A; Corlett, J N; Emma, P; Huang, Z; Kim, K -J; Lindberg, R; Murphy, J B; Neil, G P; Nguyen, D C; Pellegrini, C; Rimmer, R A; Sannibale, F; Stupakov, G; Walker, R P

    2010-06-01

    With the scientific successes of the soft X-ray FLASH facility in Germany and the recent spectacular commissioning of the Linac Coherent Light Source at SLAC, free electron lasers are poised to take center stage as the premier source of tunable, intense, coherent photons of either ultra-short time resolution or ultra-fine spectral resolution, from the far infrared to the hard X-ray regime. This paper examines the state of the art in FEL performance and the underlying enabling technologies. It evaluates the state of readiness of the three basic machine architectures—SASE FELs, seeded FELs, and FEL oscillators—for the major X-ray science user facilities on the 5–10 years time scale and examines the challenges that lie ahead for FELs to achieve their full potential throughout the entire spectral range. In soft and hard X-rays, high longitudinal coherence, in addition to full transverse coherence, will be the key performance upgrade; ideas using laser-based or self-seeding or oscillators can be expected to be qualitatively superior to today's SASE sources. Short pulses, from femtoseconds to attoseconds, can be realistically envisioned. With high repetition rate electron sources coupled to superconducting radiofrequency linear accelerators, unprecedented average beam brightness will be possible and many users would be served simultaneously by a single accelerator complex.

  20. Free electron lasers: Present status and future challenges

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, W.A. [Department of Physics, Massachusetts Institute of Technology, Bldg. 26-563, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States); Bisognano, J. [Synchrotron Radiation Center, 3731 Schneider Dr., Stoughton, WI 53589-3097 (United States); Corlett, J.N. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Emma, P.; Huang, Z. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Kim, K.-J.; Lindberg, R. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Murphy, J.B., E-mail: jbm@bnl.go [National Synchrotron Light Source, Building 725C, Upton, NY 11973 (United States); Neil, G.R. [Thomas Jefferson National Accelerator Laboratory, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Nguyen, D.C. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Pellegrini, C. [Department of Physics and Astronomy, University of California-Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); Rimmer, R.A. [Thomas Jefferson National Accelerator Laboratory, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Sannibale, F. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Stupakov, G. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Walker, R.P. [Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Zholents, A.A. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2010-06-21

    With the scientific successes of the soft X-ray FLASH facility in Germany and the recent spectacular commissioning of the Linac Coherent Light Source at SLAC, free electron lasers are poised to take center stage as the premier source of tunable, intense, coherent photons of either ultra-short time resolution or ultra-fine spectral resolution, from the far infrared to the hard X-ray regime. This paper examines the state of the art in FEL performance and the underlying enabling technologies. It evaluates the state of readiness of the three basic machine architectures-SASE FELs, seeded FELs, and FEL oscillators-for the major X-ray science user facilities on the 5-10 years time scale and examines the challenges that lie ahead for FELs to achieve their full potential throughout the entire spectral range. In soft and hard X-rays, high longitudinal coherence, in addition to full transverse coherence, will be the key performance upgrade; ideas using laser-based or self-seeding or oscillators can be expected to be qualitatively superior to today's SASE sources. Short pulses, from femtoseconds to attoseconds, can be realistically envisioned. With high repetition rate electron sources coupled to superconducting radiofrequency linear accelerators, unprecedented average beam brightness will be possible and many users would be served simultaneously by a single accelerator complex.

  1. Workshop on scientific and industrial applications of free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Difilippo, F.C. (Oak Ridge National Lab., TN (USA)); Perez, R.B. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA))

    1990-05-01

    A Workshop on Scientific and Industrial Applications of Free Electron Lasers was organized to address potential uses of a Free Electron Laser in the infrared wavelength region. A total of 13 speakers from national laboratories, universities, and the industry gave seminars to an average audience of 30 persons during June 12 and 13, 1989. The areas covered were: Free Electron Laser Technology, Chemistry and Surface Science, Atomic and Molecular Physics, Condensed Matter, and Biomedical Applications, Optical Damage, and Optoelectronics.

  2. Short Rayleigh length free electron lasers

    Directory of Open Access Journals (Sweden)

    W. B. Colson

    2006-03-01

    Full Text Available Conventional free electron laser (FEL oscillators minimize the optical mode volume around the electron beam in the undulator by making the resonator Rayleigh length about one third to one half of the undulator length. This maximizes gain and beam-mode coupling. In compact configurations of high-power infrared FELs or moderate power UV FELs, the resulting optical intensity can damage the resonator mirrors. To increase the spot size and thereby reduce the optical intensity at the mirrors below the damage threshold, a shorter Rayleigh length can be used, but the FEL interaction is significantly altered. We model this interaction using a coordinate system that expands with the rapidly diffracting optical mode from the ends of the undulator to the mirrors. Simulations show that the interaction of the strongly focused optical mode with a narrow electron beam inside the undulator distorts the optical wave front so it is no longer in the fundamental Gaussian mode. The simulations are used to study how mode distortion affects the single-pass gain in weak fields, and the steady-state extraction in strong fields.

  3. Nearly free electron states in MXenes

    Science.gov (United States)

    Khazaei, Mohammad; Ranjbar, Ahmad; Ghorbani-Asl, Mahdi; Arai, Masao; Sasaki, Taizo; Liang, Yunye; Yunoki, Seiji

    2016-05-01

    Using a set of first-principles calculations, we studied the electronic structures of two-dimensional transition metal carbides and nitrides, so called MXenes, functionalized with F, O, and OH. Our projected band structures and electron localization function analyses reveal the existence of nearly free electron (NFE) states in a variety of MXenes. The NFE states are spatially located just outside the atomic structure of MXenes and are extended parallel to the surfaces. Moreover, we found that the OH-terminated MXenes offer the NFE states energetically close to the Fermi level. In particular, the NFE states in some of the OH-terminated MXenes, such as T i2C (OH) 2,Z r2C (OH) 2,Z r2N (OH) 2,H f2C (OH) 2,H f2N (OH) 2,N b2C (OH) 2 , and T a2C (OH) 2 , are partially occupied. This is in remarkable contrast to graphene, graphane, and Mo S2 , in which their NFE states are located far above the Fermi level and thus they are unoccupied. As a prototype of such systems, we investigated the electron transport properties of H f2C (OH) 2 and found that the NFE states in H f2C (OH) 2 provide almost perfect transmission channels without nuclear scattering for electron transport. Our results indicate that these systems might find applications in nanoelectronic devices. Our findings provide new insights into the unique electronic band structures of MXenes.

  4. High Brightness Proton Beams for LHC: Needs and Means

    CERN Document Server

    Benedikt, Michael; High Energy High Intensity Hadron Beams (HHH 2004)

    2005-01-01

    Experiments [1, 2] have proven that the LHC injector chain can deliver a proton beam with the nominal characteristics (bunch intensity Nb=1.15E11 protons per bunch (ppb) in normalised rms transverse emittances of 3.5 mm.mrad), but cannot reach the ultimate performance (1.7E11 ppb in the same emittances). Moreover, in the longer term, an even higher beam brightness is required by all methods considered for increasing the LHC luminosity beyond the present ultimate level. Improvements and/or new processes are therefore needed, especially in the low energy accelerators. A number of solutions have already been imagined for the PS complex that involve new linac(s) or/and sophisticated beam gymnastics. The present capabilities and limitations of the accelerator chain are described. The needs of the possible LHC luminosity upgrades are outlined, the proposed improvements are explained and their features and performance are compared.

  5. Nonlinear optics with coherent free electron lasers

    Science.gov (United States)

    Bencivenga, F.; Capotondi, F.; Mincigrucci, R.; Cucini, R.; Manfredda, M.; Pedersoli, E.; Principi, E.; Simoncig, A.; Masciovecchio, C.

    2016-12-01

    We interpreted the recent construction of free electron laser (FELs) facilities worldwide as an unprecedented opportunity to bring concepts and methods from the scientific community working with optical lasers into the domain of x-ray science. This motivated our efforts towards the realization of FEL-based wave-mixing applications. In this article we present new extreme ultraviolet transient grating (X-TG) data from vitreous SiO2, collected using two crossed FEL pulses (photon frequency 38 eV) to generate the X-TG and a phase matched optical probing pulse (photon frequency 3.1 eV). This experiment extends our previous investigation, which was carried out on a nominally identical sample using a different FEL photon frequency (45 eV) to excite the X-TG. The present data are featured by a peak intensity of the X-TG signal substantially larger than that previously reported and by slower modulations of the X-TG signal at positive delays. These differences could be ascribed to the different FEL photon energy used in the two experiments or to differences in the sample properties. A systematic X-TG study on the same sample as a function of the FEL wavelength is needed to draw a consistent conclusion. We also discuss how the advances in the performance of the FELs, in terms of generation of fully coherent photon pulses and multi-color FEL emission, may push the development of original experimental strategies to study matter at the femtosecond-nanometer time-length scales, with the unique option of element and chemical state specificity. This would allow the development of advanced experimental tools based on wave-mixing processes, which may have a tremendous impact in the study of a large array of phenomena, ranging from nano-dynamics in complex materials to charge and energy transfer processes.

  6. Three-dimensional quasistatic model for high brightness beam dynamics simulation

    Science.gov (United States)

    Qiang, Ji; Lidia, Steve; Ryne, Robert D.; Limborg-Deprey, Cecile

    2006-04-01

    In this paper, we present a three-dimensional quasistatic model for high brightness beam dynamics simulation in rf/dc photoinjectors, rf linacs, and similar devices on parallel computers. In this model, electrostatic space-charge forces within a charged particle beam are calculated self-consistently at each time step by solving the three-dimensional Poisson equation in the beam frame and then transforming back to the laboratory frame. When the beam has a large energy spread, it is divided into a number of energy bins or slices so that the space-charge forces are calculated from the contribution of each bin and summed together. Image-charge effects from conducting photocathode are also included efficiently using a shifted-Green function method. For a beam with large aspect ratio, e.g., during emission, an integrated Green function method is used to solve the three-dimensional Poisson equation. Using this model, we studied beam transport in one Linac Coherent Light Sources photoinjector design through the first traveling wave linac with initial misalignment with respect to the accelerating axis.

  7. Dynamics of a multi-beam photonic free electron laser

    NARCIS (Netherlands)

    Lee, J.H.H.; van Dijk, M.W.; Denis, T.; van der Slot, Petrus J.M.; Boller, Klaus J.

    2012-01-01

    A photonic free-electron laser (pFEL) uses free electrons streaming through a photonic crystal (PhC) to generate tunable coherent radiation. Here, we consider a pFEL driven by a set of three low energy (~ 10 keV), low perveance (< 0.1 μP) electron beams. Using a particle-in- cell code, we numericall

  8. CAS to set up a free-electron laser facility in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ CAS has decided to establish a soft X-ray free-electron laser (SXFEL) experiment facility and an RF superconducting accelerator unit in Shanghai,according to a presentation made by Prof. ZHAO Zhentang, vice director-general of the CAS Shanghai Institute of Applied Physics (SINAP), at the 122nd session of the Eastern Forum of Science and Technology held on 11 and 12 December, 2008, in Shanghai.

  9. First lasing at the high-power free electron laser at Siberian center for photochemistry research

    Science.gov (United States)

    Antokhin, E. A.; Akberdin, R. R.; Arbuzov, V. S.; Bokov, M. A.; Bolotin, V. P.; Burenkov, D. B.; Bushuev, A. A.; Veremeenko, V. F.; Vinokurov, N. A.; Vobly, P. D.; Gavrilov, N. G.; Gorniker, E. I.; Gorchakov, K. M.; Grigoryev, V. N.; Gudkov, B. A.; Davydov, A. V.; Deichuli, O. I.; Dementyev, E. N.; Dovzhenko, B. A.; Dubrovin, A. N.; Evtushenko, Yu. A.; Zagorodnikov, E. I.; Zaigraeva, N. S.; Zakutov, E. M.; Erokhin, A. I.; Kayran, D. A.; Kiselev, O. B.; Knyazev, B. A.; Kozak, V. R.; Kolmogorov, V. V.; Kolobanov, E. I.; Kondakov, A. A.; Kondakova, N. L.; Krutikhin, S. A.; Kryuchkov, A. M.; Kubarev, V. V.; Kulipanov, G. N.; Kuper, E. A.; Kuptsov, I. V.; Kurkin, G. Ya.; Labutskaya, E. A.; Leontyevskaya, L. G.; Loskutov, V. Yu.; Matveenko, A. N.; Medvedev, L. E.; Medvedko, A. S.; Miginsky, S. V.; Mironenko, L. A.; Motygin, S. V.; Oreshkov, A. D.; Ovchar, V. K.; Osipov, V. N.; Persov, B. Z.; Petrov, S. P.; Petrov, V. M.; Pilan, A. M.; Poletaev, I. V.; Polyanskiy, A. V.; Popik, V. M.; Popov, A. M.; Rotov, E. A.; Salikova, T. V.; Sedliarov, I. K.; Selivanov, P. A.; Serednyakov, S. S.; Skrinsky, A. N.; Tararyshkin, S. V.; Timoshina, L. A.; Tribendis, A. G.; Kholopov, M. A.; Cherepanov, V. P.; Shevchenko, O. A.; Shteinke, A. R.; Shubin, E. I.; Scheglov, M. A.

    2004-08-01

    The first lasing near wavelength 140 μm was achieved in April 2003 on a high-power free electron laser (FEL) constructed at the Siberian Center for Photochemical Research. In this paper, we briefly describe the design of FEL driven by an accelerator-recuperator. Characteristics of the electron beam and terahertz laser radiation, obtained at the first experiments, are also presented in the paper.

  10. Characteristics of radiation safety for synchrotron radiation and X-ray free electron laser facilities.

    Science.gov (United States)

    Asano, Yoshihiro

    2011-07-01

    Radiation safety problems are discussed for typical electron accelerators, synchrotron radiation (SR) facilities and X-ray free electron laser (XFEL) facilities. The radiation sources at the beamline of the facilities are SR, including XFEL, gas bremsstrahlung and high-energy gamma ray and photo-neutrons due to electron beam loss. The radiation safety problems for each source are compared by using 8 GeV class SR and XFEL facilities as an example.

  11. Condensed matter research using the UCSB FEL. [Univ. of California, Santa Barbara Free Electron Laser project

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The University of California, Santa Barbara (UCSB) Free Electron Laser (FEL) project was initiated in 1981 to test the idea of using an electrostatic accelerator in a recirculating beam mode to produce high-power, continuously tunable, coherent far infrared radiation. The development and application of this device to condensed matter research are briefly recounted. Emphasis was on semiconductor research and two-photon experiments. (RWR)

  12. The History of X-ray Free-Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C.; /UCLA /SLAC

    2012-06-28

    The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provided the best X-ray sources. The LCLS has set a new standard, with a peak X-ray brightness higher by ten orders of magnitudes and pulse duration shorter by three orders of magnitudes. LCLS opens a new window in the exploration of matter at the atomic and molecular scales of length and time. Taking a motion picture of chemical processes in a few femtoseconds or less, unraveling the structure and dynamics of complex molecular systems, like proteins, are some of the exciting experiments made possible by LCLS and the other X-ray FELs now being built in Europe and Asia. In this paper, we describe the history of the many theoretical, experimental and technological discoveries and innovations, starting from the 1960s and 1970s, leading to the development of LCLS.

  13. Ultraviolet Free Electron Laser Facility preliminary design report

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. [ed.

    1993-02-01

    This document, the Preliminary Design Report (PDR) for the Brookhaven Ultraviolet Free Electron Laser (UV FEL) facility, describes all the elements of a facility proposed to meet the needs of a research community which requires ultraviolet sources not currently available as laboratory based lasers. Further, for these experiments, the requisite properties are not extant in either the existing second or upcoming third generation synchrotron light sources. This document is the result of our effort at BNL to identify potential users, determine the requirements of their experiments, and to design a facility which can not only satisfy the existing need, but have adequate flexibility for possible future extensions as need dictates and as evolving technology allows. The PDR is comprised of three volumes. In this, the first volume, background for the development of the proposal is given, including descriptions of the UV FEL facility, and representative examples of the science it was designed to perform. Discussion of the limitations and potential directions for growth are also included. A detailed description of the facility design is then provided, which addresses the accelerator, optical, and experimental systems. Information regarding the conventional construction for the facility is contained in an addendum to volume one (IA).

  14. Ultraviolet Free Electron Laser Facility preliminary design report

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (ed.)

    1993-02-01

    This document, the Preliminary Design Report (PDR) for the Brookhaven Ultraviolet Free Electron Laser (UV FEL) facility, describes all the elements of a facility proposed to meet the needs of a research community which requires ultraviolet sources not currently available as laboratory based lasers. Further, for these experiments, the requisite properties are not extant in either the existing second or upcoming third generation synchrotron light sources. This document is the result of our effort at BNL to identify potential users, determine the requirements of their experiments, and to design a facility which can not only satisfy the existing need, but have adequate flexibility for possible future extensions as need dictates and as evolving technology allows. The PDR is comprised of three volumes. In this, the first volume, background for the development of the proposal is given, including descriptions of the UV FEL facility, and representative examples of the science it was designed to perform. Discussion of the limitations and potential directions for growth are also included. A detailed description of the facility design is then provided, which addresses the accelerator, optical, and experimental systems. Information regarding the conventional construction for the facility is contained in an addendum to volume one (IA).

  15. Attosecond Hard X-ray Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar

    2013-03-01

    Full Text Available In this paper, several schemes of soft X-ray and hard X-ray free electron lasers (XFEL and their progress are reviewed. Self-amplified spontaneous emission (SASE schemes, the high gain harmonic generation (HGHG scheme and various enhancement schemes through seeding and beam manipulations are discussed, especially in view of the generation of attosecond X-ray pulses. Our recent work on the generation of attosecond hard X-ray pulses is also discussed. In our study, the enhanced SASE scheme is utilized, using electron beam parameters of an XFEL under construction at Pohang Accelerator Laboratory (PAL. Laser, chicane and electron beam parameters are optimized to generate an isolated attosecond hard X-ray pulse at 0.1 nm (12.4 keV. The simulations show that the manipulation of electron energy beam profile may lead to the generation of an isolated attosecond hard X-ray of 150 attosecond pulse at 0.1 nm.

  16. Experimental demonstration of longitudinal beam phase space linearizer in a free-electron laser facility by corrugated structures

    CERN Document Server

    Deng, Haixiao; Feng, Chao; Zhang, Tong; Wang, Xingtao; Lan, Taihe; Feng, Lie; Zhang, Wenyan; Liu, Xiaoqing; Yao, Haifeng; Shen, Lei; Li, Bin; Zhang, Junqiang; Li, Xuan; Fang, Wencheng; Wang, Dan; Couprie, Marie-emmanuelle; Lin, Guoqiang; Liu, Bo; Gu, Qiang; Wang, Dong; Zhao, Zhentang

    2014-01-01

    Removal of residual linear energy chirp and intrinsic nonlinear energy curvature in the relativistic electron beam from radiofrequency linear accelerator is of paramount importance for efficient lasing of a high-gain free-electron laser. Recently, it was theoretically and experimentally demonstrated that the longitudinal wakefield excited by the electrons itself in the corrugated structure allows for precise control of the electron beam phase space. In this Letter, we report the first utilization of a corrugated structure as beam linearizer in the operation of a seeded free-electron laser driven by a 140 MeV linear accelerator, where a gain of ~10,000 over spontaneous emission was achieved at the second harmonic of the 1047 nm seed laser, and a free-electron laser bandwidth narrowing by about 50% was observed, in good agreement with the theoretical expectations.

  17. Application of FPGA technology for control of superconducting TESLA cavities in free electron laser

    Science.gov (United States)

    Pozniak, Krzysztof T.

    2006-10-01

    Contemporary fundamental research in physics, biology, chemistry, pharmacology, material technology and other uses frequently methods basing on collision of high energy particles or penetration of matter with ultra-short electromagnetic waves. Kinetic energy of involved particles, considerably greater than GeV, is generated in accelerators of unique construction. The paper presents a digest of working principles of accelerators. There are characterized research methods which use accelerators. A method to stabilize the accelerating EM field in superconducting (SC) resonant cavity was presented. An example was given of usage of TESLA cavities in linear accelerator propelling the FLASH free electron laser (FEL) in DESY, Hamburg. Electronic and photonic control system was debated. The system bases on advanced FPGA circuits and cooperating fast DSP microprocessor chips. Examples of practical solutions were described. Test results of the debated systems in the real-time conditions were given.

  18. W-Band Free Electron Laser for High Gradient Structure Research

    Science.gov (United States)

    Lidia, S. M.; Whittum, D. H.; Donohue, J. T.

    1997-05-01

    We discuss the use of a free electron laser in support of material stress studies of W-band high-gradient accelerating structures. We propose the use of the linear induction accelerator LELIA (CEA/CESTA, France) to generate a 1-kiloamp, 80-ns FWHM electron pulse. We present a design for a helical FEL TE_11 amplifier that will generate high peak power (100's MW) at 93 GHz. We support our design with analytical estimates of gain, and with numerical simulations of power and phase development.

  19. Measurements and analysis of a high-brightness electron beam collimated in a magnetic bunch compressor

    Directory of Open Access Journals (Sweden)

    F. Zhou

    2015-05-01

    Full Text Available A collimator located in a magnetic bunch compressor of a linear accelerator driven x-ray free electron laser has many potential applications, such as the removal of horns in the current distribution, the generation of ultrashort beams, and as a diagnostic of the beam slice emittance. Collective effects, however, are a major concern in applying the technique. Systematic measurements of emittance and analysis were performed using a collimator in the first bunch compressor of the Linac Coherent Light Source (LCLS. In the nominal, undercompressed configuration using the collimator we find that the y emittance (nonbending plane is not increased, and the x emittance (in the bending plane is increased by about 25%, in comparison to the injector emittance. From the analysis we conclude that the parasitic effects associated with this method are dominated by coherent synchrotron radiation (CSR, which causes a “systematic error” for measuring slice emittance at the bending plane using the collimation method. In general, we find good agreement between the measurements and simulations including CSR. However, for overcompressed beams at smaller collimator gaps, an extra emittance increase is found that does not agree with 1D simulations and is not understood.

  20. Advanced Transport Systems for Electron Beams in High Brightness Accelerators and FELs

    Science.gov (United States)

    1993-07-19

    1983). note that a value of K as low as 0.17% already leads to (121 G. J. Caouo F. Rainer. W. E. Martin, D. S. Prono , appreciable BBU reduction in a...529 (1992). 28 S 0 S0. J. Cepomnt, F. Rainer. W. E. MartKiD. S3.. Prono , and A. G. Cole_ j6 Phys. Rev. LUt. 57. 1591 (1936).i.475 2.495 2-495 2.505...Neil, LS. Hall, and RIK. Cooper, Part. AcceL 9, 213 (1979). 6. G. J. Caporaso, F. Rainer, W. E. Martin, D. S. Prono , and A. G. Cole, Phys. Rev. Lett. 57

  1. Prebunched-beam free electron maser

    Science.gov (United States)

    Arbel, M.; Ben-Chaim, D.; Cohen, M.; Draznin, M.; Eichenbaum, A.; Gover, Abraham; Kleinman, H.; Kugel, A.; Pinhasi, Yosef; Witman, S.; Yakover, Y. M.

    1994-05-01

    The development status of a prebunched FEM is described. We are developing a 70 KeV FEM to allow high gain wideband operation and to enable variation of the degree of prebunching. We intend to investigate its operation as an amplifier and as an oscillator. Effects of prebunching, frequency variation, linear and nonlinear effects, will be investigated. The prebuncher consists of a Pierce e-gun followed by a beam modulating section. The prebunched beam is accelerated to 70 KeV and injected into a planar wiggler containing a waveguide. The results obtained to date will be presented. These include: characterization of the e-gun, e-beam transport to and through the wiggler, use of field modifying permanent magnets near the entrance and along the wiggler to obtain good e-beam transport through the wiggler, waveguide selection and characterization.

  2. German and U.S. laboratories to collaborate on the development of X-ray free electron lasers

    CERN Multimedia

    Calder, N

    2002-01-01

    Germany's leading particle physics and synchrotron radiation laboratory (DESY), and the U.S. Department of Energy's Stanford Linear Accelerator Center (SLAC), have signed a Memorandum of Understanding (MoU) to establish a unique international collaboration for the development of X-ray free-electron lasers (1 page).

  3. Free-electron laser operation with a superconducting radio-frequency photoinjector at ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Teichert, J., E-mail: j.teichert@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Arnold, A.; Büttig, H.; Justus, M. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Kamps, T. [Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Lehnert, U. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Lu, P. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Michel, P.; Murcek, P. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Rudolph, J. [Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Schurig, R.; Seidel, W. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Vennekate, H. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Will, I. [Max-Born-Institut, Berlin, Max-Born-Str. 2a, 12489 Berlin (Germany); Xiang, R. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany)

    2014-04-11

    At the radiation source ELBE a superconducting radio-frequency photoinjector (SRF gun) was developed and put into operation. Since 2010 the gun has delivered beam into the ELBE linac. A new driver laser with 13 MHz pulse repetition rate allows now to operate the free-electron lasers (FELs) with the SRF gun. This paper reports on the first lasing experiment with the far-infrared FEL at ELBE, describes the hardware, the electron beam parameters and the measurement of the FEL infrared radiation output. - Highlights: • The superconducting RF gun produces beam with Cs{sub 2}Te photocathodes. • The SRF gun operates as an injector for the ELBE linear accelerator. • First lasing of an infrared free-electron laser with an SRF gun.

  4. A ferroelectric electron gun in a free-electron maser experiment

    CERN Document Server

    Einat, M; Rosenman, G

    2002-01-01

    An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

  5. Novosibirsk Free Electron Laser: Recent Achievements and Future Prospects

    Science.gov (United States)

    Shevchenko, O. A.; Arbuzov, V. S.; Vinokurov, N. A.; Vobly, P. D.; Volkov, V. N.; Getmanov, Ya. V.; Davidyuk, I. V.; Deychuly, O. I.; Dementyev, E. N.; Dovzhenko, B. A.; Knyazev, B. A.; Kolobanov, E. I.; Kondakov, A. A.; Kozak, V. R.; Kozyrev, E. V.; Kubarev, V. V.; Kulipanov, G. N.; Kuper, E. A.; Kuptsov, I. V.; Kurkin, G. Ya.; Krutikhin, S. A.; Medvedev, L. E.; Motygin, S. V.; Ovchar, V. K.; Osipov, V. N.; Petrov, V. M.; Pilan, A. M.; Popik, V. M.; Repkov, V. V.; Salikova, T. V.; Sedlyarov, I. K.; Serednyakov, S. S.; Skrinsky, A. N.; Tararyshkin, S. V.; Tribendis, A. G.; Cheskidov, V. G.; Chernov, K. N.; Shcheglov, M. A.

    2017-02-01

    Free electron lasers (FELs) are unique sources of electromagnetic radiation with tunable wavelength. A high-power FEL has been created at the G. I.Budker Institute for Nuclear Physics. Its radiation frequency can be tuned over a wide range in the terahertz and infrared spectral ranges. As the source of electron bunches, this FEL uses a multi-turn energy-recovery linac, which has five straight sections. Three sections are used for three FELs which operate in different wavelength ranges (90-240 μm for the first, 37-80 μm for the second, and 5-20 μm for the third ones). The first and the second FELs were commissioned in 2003 and 2009, respectively. They are used for various applied and research problems now. The third FEL is installed on the last, forth accelerator loop, in which the electron energy is the maximum. It comprises three undulator sections and a 40 m optical cavity. The first lasing of this FEL was obtained in the summer of 2015. The radiation wavelength was 9 μm and the average power was about 100 W. The design power is 1 kW at a pulse repetition rate of 3.75 MHz. Radiation of the third FEL will be delivered to user stations from the protected hall in the near future. The third FEL commissioning results are presented and the current status of the first and second FELs as well as their future development prospects are described.

  6. Accelerator Technology Division

    Science.gov (United States)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  7. Experimental Investigation of Multibunch, Multipass Beam Breakup in the Jefferson Laboratory Free Electron Laser Upgrade Driver

    Energy Technology Data Exchange (ETDEWEB)

    Christopher Tennant; David Douglas; Kevin Jordan; Nikolitsa Merminga; Eduard Pozdeyev; Haipeng Wang; Todd I. Smith; Stefan Simrock; Ivan Bazarov; Georg Hoffstaetter

    2006-03-24

    In recirculating accelerators, and in particular energy recovery linacs (ERLs), the maximum current can be limited by multipass, multibunch beam breakup (BBU), which occurs when the electron beam interacts with the higher-order modes (HOMs) of an accelerating cavity on the accelerating pass and again on the energy recovering pass. This effect is of particular concern in the design of modern high average current energy recovery accelerators utilizing superconducting RF technology. Experimental characterization and observations of the instability at the Jefferson Laboratory 10 kW Free Electron Laser (FEL) are presented. Measurements of the threshold current for the instability are made under a variety of beam conditions and compared to the predictions of several BBU simulation codes. This represents the first time in which the codes have been experimentally benchmarked. With BBU posing a threat to high current beam operation in the FEL Driver, several suppression schemes were developed.

  8. Development of components for the high brightness laser. Final report May 77-Jun 80

    Energy Technology Data Exchange (ETDEWEB)

    Garmire, E.

    1980-10-01

    In 1979 DBR lasers were fabricated and their properties studied. Further investigations were undertaken of the beam expander, to determine its potential for the high brightness laser. From this data it was determined that a design change for the high brightness laser is required. This design change is described. In addition, measurements were made on laser amplification to compare this method of achieving higher power compared to the coupled diode arrays. Finally, as a spin-off of this research, a new design for a single mode laser was discovered, using the active/passive laser, a configuration which was fabricated as a first step toward fabrication of DBR lasers. Each of these research efforts are described in this report. Monolithic integration of the necessary components on one substrate for the high brightness laser has been hindered by problems in material and fabrication uniformity. This will be described, and projections for future development will be outlined.

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

    Directory of Open Access Journals (Sweden)

    Christopher Behrens

    2012-02-01

    Full Text Available 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-30

    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.

  11. Beam shaping design for compact and high-brightness fiber-coupled laser-diode system.

    Science.gov (United States)

    Yu, Junhong; Guo, Linui; Wu, Hualing; Wang, Zhao; Tan, Hao; Gao, Songxin; Wu, Deyong; Zhang, Kai

    2015-06-20

    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. A compact and high-brightness fiber-coupled system has been designed based on a significant beam shaping method. The laser-diode stack consists of eight mini-bars and is effectively coupled into a standard 100 μm core diameter and NA=0.22 fiber. The simulative result indicates that the module will have an output power over 440 W. Using this technique, compactness and high-brightness production of a fiber-coupled laser-diode module is possible.

  12. Comparison of the coherent radiation-induced microbunching instability in a free-electron laser and a magnetic chicane

    Directory of Open Access Journals (Sweden)

    S. Reiche

    2003-04-01

    Full Text Available A self-amplified spontaneous emission free-electron laser (SASE FEL is a device which is based on the creation of a very intense, relativistic electron beam which has very little temperature in all three phase planes. The beam in this system is described as having “high brightness,” and when it is bent repetitively in a magnetic undulator, undergoes a radiation-mediated microbunching instability. This instability can amplify the original radiation amplitude at a particular, resonant wavelength by many orders of magnitude. In order to obtain high brightness beams, it is necessary to compress them to obtain higher currents than available from the electron source. Compression is accomplished by the use of magnetic chicanes, which are quite similar to, if much longer than, a single period of the undulator. It should not be surprising that such chicanes also support a radiation-mediated microbunching interaction, which has recently been investigated, and has been termed coherent synchrotron radiation (CSR instability. The purpose of this paper is to compare and contrast the characteristics of the closely related FEL and CSR microbunching instabilities. We show that a high-gain regime of the CSR instability exists which is formally similar to the FEL instability.

  13. A spectral unaveraged algorithm for free electron laser simulations

    Energy Technology Data Exchange (ETDEWEB)

    Andriyash, I.A., E-mail: igor.andriyash@gmail.com [Laboratoire d' Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Lehe, R.; Malka, V. [Laboratoire d' Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

    2015-02-01

    We propose and discuss a numerical method to model electromagnetic emission from the oscillating relativistic charged particles and its coherent amplification. The developed technique is well suited for free electron laser simulations, but it may also be useful for a wider range of physical problems involving resonant field–particles interactions. The algorithm integrates the unaveraged coupled equations for the particles and the electromagnetic fields in a discrete spectral domain. Using this algorithm, it is possible to perform full three-dimensional or axisymmetric simulations of short-wavelength amplification. In this paper we describe the method, its implementation, and we present examples of free electron laser simulations comparing the results with the ones provided by commonly known free electron laser codes.

  14. A spectral unaveraged algorithm for free electron laser simulations

    CERN Document Server

    Andriyash, Igor A; Malka, Victor

    2014-01-01

    We propose and discuss a numerical method to model electromagnetic emission from the oscillating relativistic charged particles and its coherent amplification. The developed technique is well suited for free electron laser simulations, but it may also be useful for a wider range of physical problems involving resonant field-particles interactions. The algorithm integrates the unaveraged coupled equations for the particles and the electromagnetic fields in a discrete spectral domain. Using this algorithm, it is possible to perform full three-dimensional simulations of short-wavelength amplification. In this paper we describe the algorithm, its implementation, and we present examples of free electron laser simulations comparing the results with the ones provided by commonly known free electron laser codes.

  15. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory.

    Science.gov (United States)

    Weathersby, S P; Brown, G; Centurion, M; Chase, T F; Coffee, R; Corbett, J; Eichner, J P; Frisch, J C; Fry, A R; Gühr, M; Hartmann, N; Hast, C; Hettel, R; Jobe, R K; Jongewaard, E N; Lewandowski, J R; Li, R K; Lindenberg, A M; Makasyuk, I; May, J E; McCormick, D; Nguyen, M N; Reid, A H; Shen, X; Sokolowski-Tinten, K; Vecchione, T; Vetter, S L; Wu, J; Yang, J; Dürr, H A; Wang, X J

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  16. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, S. P. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Brown, G. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Centurion, M. [University of Nebraska-Lincoln, 855 N 16th Street, Lincoln, Nebraska 68588, USA; Chase, T. F. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Coffee, R. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Corbett, J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Eichner, J. P. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Frisch, J. C. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Fry, A. R. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Gühr, M. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Hartmann, N. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Hast, C. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Hettel, R. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Jobe, R. K. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Jongewaard, E. N. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Lewandowski, J. R. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Li, R. K. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Lindenberg, A. M. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Makasyuk, I. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; May, J. E. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Nguyen, M. N. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Reid, A. H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Shen, X. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Sokolowski-Tinten, K. [University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany; Vecchione, T. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Vetter, S. L. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Wu, J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Yang, J. [University of Nebraska-Lincoln, 855 N 16th Street, Lincoln, Nebraska 68588, USA; Dürr, H. A. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA; Wang, X. J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  17. Suppression of microbunching instability using bending magnets in free-electron-laser linacs.

    Science.gov (United States)

    Qiang, Ji; Mitchell, Chad E; Venturini, Marco

    2013-08-02

    The microbunching instability driven by collective effects of the beam inside an accelerator can significantly degrade the final electron beam quality for free electron laser (FEL) radiation. In this Letter, we propose an inexpensive scheme to suppress such an instability in accelerators for next generation FEL light sources. Instead of using an expensive device such as a laser heater or RF deflecting cavities, this scheme uses longitudinal mixing associated with the transverse spread of the beam through bending magnets inside the accelerator transport system to suppress the instability. The final uncorrelated energy spread increases roughly by the current compression factor, which is important in seeded FEL schemes in order to achieve high harmonic short-wavelength x-ray radiation.

  18. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S G; Barty, C P J; Betts, S M; Brown, W J; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Hartemann, F V; Kuba, J; LaSage, G P; Rosenzweig, J B; Slaughter, D R; Springer, P T; Tremaine, A M

    2003-07-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

  19. Gain of double-slab Cherenkov free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [Institute for laser Technology, suita, Osaka 565-0871 (Japan)], E-mail: dazhi_li@hotmail.com; Huo, G. [Petroleum development center, Shengli Oilfield, SINOPEC, Dongying 257001 (China); Imasak, K. [Institute for laser Technology, suita, Osaka 565-0871 (Japan); Asakawa, M. [Department of pure and applied physics, Faculty of Engineering Science, Kansai University, Osaka 564-8680 (Japan)

    2009-07-21

    A formula is derived for the small-signal gain of a double-slab Cherenkov free-electron laser. The simplified model is composed of a rectangular wave-guide partially filled with two lined parallel dielectric slabs and a sheet electron beam. The theory describes the electron beam as a plasma dielectric moving between the two dielectric slabs. With the help of hydrodynamic approximation, we derived the dispersion equation and the formula of small-signal gain. Through numerical computing, we studied an ongoing experiment of double-slab Cherenkov free-electron laser, and worked out the synchronous frequency and single-pass gain.

  20. Chaotic dynamics in a storage-ring Free Electron Laser

    CERN Document Server

    De Ninno, G; Bruni, C; Couprie, Marie Emmanuelle

    2002-01-01

    The temporal dynamics of a storage-ring Free Electron Laser is here investigated with particular attention to the case in which an external modulation is applied to the laser-electron beam detuning. The system is shown to produce bifurcations, multi-furcations as well as chaotic regimes. The peculiarities of this phenomenon with respect to the analogous behavior displayed by conventional laser sources are pointed out. Theoretical results, obtained by means of a phenomenological model reproducing the evolution of the main statistical parameters of the system, are shown to be in a good agreement with experiments carried out on the Super-ACO Free Electron Laser.

  1. Radiation control aspects of the civil construction for a high power free electron laser (FEL) facility

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, T.; Neil, G.; Stapleton, G.

    1996-12-31

    The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building.

  2. Large-Scale Production of Carbon Nanotubes Using the Jefferson Lab Free Electron Laser

    Science.gov (United States)

    Holloway, Brian C.

    2003-01-01

    We report on our interdisciplinary program to use the Free Electron Laser (FEL) at the Thomas Jefferson National Accelerator Facility (J-Lab) for high-volume pulsed laser vaporization synthesis of carbon nanotubes. Based in part on the funding of from this project, a novel nanotube production system was designed, tested, and patented. Using this new system nanotube production rates over 100 times faster than conventional laser systems were achieved. Analysis of the material produced shows that it is of as high a quality as the standard laser-based materials.

  3. Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning

    Science.gov (United States)

    Sanchez-Gonzalez, A.; Micaelli, P.; Olivier, C.; Barillot, T. R.; Ilchen, M.; Lutman, A. A.; Marinelli, A.; Maxwell, T.; Achner, A.; Agåker, M.; Berrah, N.; Bostedt, C.; Bozek, J. D.; Buck, J.; Bucksbaum, P. H.; Montero, S. Carron; Cooper, B.; Cryan, J. P.; Dong, M.; Feifel, R.; Frasinski, L. J.; Fukuzawa, H.; Galler, A.; Hartmann, G.; Hartmann, N.; Helml, W.; Johnson, A. S.; Knie, A.; Lindahl, A. O.; Liu, J.; Motomura, K.; Mucke, M.; O'Grady, C.; Rubensson, J.-E.; Simpson, E. R.; Squibb, R. J.; Såthe, C.; Ueda, K.; Vacher, M.; Walke, D. J.; Zhaunerchyk, V.; Coffee, R. N.; Marangos, J. P.

    2017-06-01

    Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.

  4. Far field acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  5. First microwave generation in the FOM free-electron maser

    NARCIS (Netherlands)

    Verhoeven, A. G. A.; Bongers, W. A.; Bratman, V. L.; Caplan, M.; Denisov, G. G.; van der Geer, C. A. J.; Manintveld, P.; Poelman, A. J.; Pluygers, J.; Shmelyov, M. Y.; Smeets, P. H. M.; Sterk, A. B.; Urbanus, W. H.

    1998-01-01

    A free-electron maser (FEM) has been built as a pilot experiment for a millimetre-wave source for applications on future fusion research devices such as ITER, the International Tokamak Experimental Reactor. A unique feature of the Dutch fusion FEM is the possibility to tune the frequency over the en

  6. First high power experiments with the Dutch free electron maser

    NARCIS (Netherlands)

    Verhoeven, A. G. A.; Bongers, W. A.; Bratman, V. L.; Caplan, M.; Denisov, G. G.; van Dijk, G.; van der Geer, C. A. J.; Manintveld, P.; Poelman, A. J.; Pluygers, J.; Shmelyov, M. Y.; Smeets, P. H. M.; Sterk, A. B.; Urbanus, W. H.

    1998-01-01

    A free electron maser (FEM) has been built as a mm-wave source for applications on future fusion research devices such as ITER, the international tokamak experimental reactor [M. A. Makowski, F. Elio, and D. Loeser, April 97, Proc. 10th Workshop on ECE and ECRH, EC10, 549-559. World Scientific (1998

  7. Study of Short Bunches at the Free Electron Laser CLIO

    CERN Document Server

    Delerue, Nicolas; Khodnevych, Vitalii; Berthet, Jean-Paul; Glotin, Francois; Ortega, Jean-Michel; Prazeres, Rui

    2016-01-01

    CLIO is a Free Electron Laser based on a thermionic electron gun. In its normal operating mode it delivers electron 8 pulses but studies are ongoing to shorten the pulses to about 1 ps. We report on simulations showing how the pulse can be shortened and the expected signal yield from several bunch length diagnostics (Coherent Transition Radiation, Coherent Smith Purcell Radiation).

  8. Free electron lifetime achievements in liquid Argon imaging TPC

    Energy Technology Data Exchange (ETDEWEB)

    Baibussinov, B; Ceolin, M Baldo; Centro, S; Cieslik, K; Farnese, C; Fava, A; Gibin, D; Guglielmi, A; Meng, G; Pietropaolo, F; Varanini, F; Ventura, S [INFN, Sezione di Padova via Marzolo 8, I-35131 Padova (Italy); Calligarich, E [INFN, Sezione di Pavia via Bassi 6, I-27100 Pavia (Italy); Rubbia, C, E-mail: Carlo.Rubbia@cern.c [Laboratori Nazionali del Gran Sasso dell' INFN I-67010 Assergi (Italy)

    2010-03-15

    A key feature for the success of the liquid Argon imaging TPC (LAr-TPC) technology is the industrial purification against electro-negative impurities, especially Oxygen and Nitrogen remnants, which have to be continuously kept at an exceptionally low level by filtering and recirculating liquid Argon. Improved purification techniques have been applied to a 120 liters LAr-TPC test facility in the INFN-LNL laboratory. Through-going muon tracks have been used to determine the free electron lifetime in liquid Argon against electro-negative impurities. The short path length here observed (30 cm) is compensated by the high accuracy in the observation of the specific ionization of cosmic ray muons at sea level as a function of the drift distance. A free electron lifetime of tau {approx} (21.4{sup +7.3}{sub -4.3}) ms, namely > 15.8 ms at 90% C.L. has been observed over several weeks under stable conditions, corresponding to a residual Oxygen equivalent of {approx} 15 ppt (part per trillion). At 500 V/cm, the free electron speed is 1.5 mm/mus. In a LAr-TPC a free electron lifetime in excess of 15 ms corresponds for instance to an attenuation of less than 20% after a drift path of 5 m, opening the way to the operation of the LAr-TPC with exceptionally long drift distances.

  9. Applications of free electron lasers in the UV

    Energy Technology Data Exchange (ETDEWEB)

    Couprie, M.E.

    1994-12-31

    The first applications of the UV Free Electron Lasers (FEL) show the advance to a stage of maturity for such sources. Two-color experiments coupling storage ring FEL and synchrotron radiation offer the wide range of use. (TEC). 26 refs., 7 figs., 2 tabs.

  10. Cavity ring down spectroscopy with a free-electron laser

    NARCIS (Netherlands)

    Engeln, R.; van den Berg, E.; Meijer, G.; Lin, L.; Knippels, G.M.H.; van der Meer, A. F. G.

    1997-01-01

    A cavity ring down (CRD) absorption experiment is performed with a free-electron laser (FEL) operating in the 10-11 mu m region. A short infrared pulse of approximately 20 ns, sliced from the much longer FEL pulse, is used to measure CRD spectra of ethylene in two different ways. First, ''

  11. Modeling paraxial wave propagation in free-electron laser oscillators

    NARCIS (Netherlands)

    Karssenberg, J.G.; van der Slot, Petrus J.M.; Volokhine, I.; Verschuur, Jeroen W.J.; Boller, Klaus J.

    2006-01-01

    Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for

  12. Modeling paraxial wave propagation in free-electron laser oscillators

    NARCIS (Netherlands)

    Karssenberg, J.G.; Slot, van der P.J.M.; Volokhine, I.V.; Verschuur, J.W.J.; Boller, K.J.

    2006-01-01

    Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for exam

  13. RoHS/Pb-free Electronics for DoD?: Managing the Pb-free Electronics Transition

    Science.gov (United States)

    2010-06-14

    GEIA = Government Electronics & Information Technology Association AMC = Avionics Maintenance Conference Pb-free Electronics Risk Management PERM... AlA EMC PERM Consortium Management PERM International Beneficiaries ............... ?.~~~-~·i...elected) - AlA Liaison/Executive Secretary -DoD LSA4 for Soldering Technologies -Executive Committee Ex-Chair Task Team Leads International Advisory

  14. Conductively cooled high-power high-brightness bars and fiber-coupled arrays

    Science.gov (United States)

    Zhou, Hailong; Mondry, Mark; Fouksman, Michael; Weiss, Eli; Anikitchev, Serguei; Kennedy, Keith; Li, Jun; Zucker, Erik; Rudy, Paul; Kongas, Jukka; Haapamaa, Jouko; Lehkonen, Sami

    2005-03-01

    Solid-state-laser and fiber laser pumping, reprographics, medical and materials processing applications require high power, high-brightness bars and fiber-coupled arrays. Conductively cooled laser diode bars allow customers to simplify system design and reduce operational size, weight, and costs. We present results on next generation high brightness, high reliability bars and fiber-coupled arrays at 790-830 nm, 940 nm and 980 nm wavelengths. By using novel epitaxial structures, we have demonstrated highly reliable 808 nm, 30% fill-factor conductively cooled bars operating at 60W CW mode, corresponding to a linear power density (LPD) of 20 mW/&mum. At 25°C, the bars have shown greater than 50% wall-plug-efficiency (WPE) when operating at 60W. Our novel approach has also reduced the fast-axis divergence FWHM from 31° to less than 24°. These bars have a 50% brightness improvement compared to our standard products with this geometry. At 980nm, we have demonstrated greater than 100W CW from 20% fill-factor conductively cooled bars, corresponding to a LPD of 50 mW/μm. At 25°C, the WPE for 976nm bars consistently peaks above 65% and remains greater than 60% at 100W. We coupled the beam output from those high-brightness bars into fiber-array-packages ("FAPs"), and we also achieved high-brightness and high-efficiency FAPs. We demonstrated 60W from a 600μm core-diameter fiber-bundle with a high WPE of 55%, and a low numerical aperture of 0.115. The brightness of such FAPs is four times higher than our standard high-power 40W FAP products at Coherent. Ongoing life test data suggests an extrapolated lifetime greater than 10,000 hours at 80W CW operating-condition based on 30%FF conductively cooled bar geometry.

  15. Volume-scalable high-brightness three-dimensional visible light source

    Science.gov (United States)

    Subramania, Ganapathi; Fischer, Arthur J; Wang, George T; Li, Qiming

    2014-02-18

    A volume-scalable, high-brightness, electrically driven visible light source comprises a three-dimensional photonic crystal (3DPC) comprising one or more direct bandgap semiconductors. The improved light emission performance of the invention is achieved based on the enhancement of radiative emission of light emitters placed inside a 3DPC due to the strong modification of the photonic density-of-states engendered by the 3DPC.

  16. Preparatory procedure and equipment for the European x-ray free electron laser cavity implementation

    Energy Technology Data Exchange (ETDEWEB)

    Reschke, D.; Bandelmann, R.; Buettner, T.; Escherich, K.; Goessel, A.; v.d.Horst, B.; Iversen, J.; Klinke, D.; Kreps, G.; Krupka, N.; Lilje, L.; /DESY /Fermilab

    2010-07-01

    The European x-ray free electron laser is under construction at Deutsches Elektronen-Synchrotron (DESY). The electron beam energy of up to 17.5 GeV will be achieved by using superconducting accelerator technology. Final prototyping, industrialization, and new infrastructure are the actual challenges with respect to the accelerating cavities. This paper describes the preparation strategy optimized for the cavity preparation procedure in industry. For the industrial fabrication and preparation, several new hardware components have been already developed at DESY. The design and construction of a semiautomated rf-measurement machine for dumbbells and end groups are described. In a collaboration among FNAL, KEK, and DESY, an automatic cavity tuning machine has been designed and four machines are under construction. The functionality of these machines with special attention to safety aspects is described in this paper. A new high pressure rinsing system has been developed and is operational.

  17. Crystallographic data processing for free-electron laser sources

    Energy Technology Data Exchange (ETDEWEB)

    White, Thomas A., E-mail: taw@physics.org; Barty, Anton; Stellato, Francesco [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Holton, James M. [University of California, San Francisco, CA 94158 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kirian, Richard A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287 (United States); Zatsepin, Nadia A. [Arizona State University, Tempe, AZ 85287 (United States); Chapman, Henry N. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2013-07-01

    A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

  18. Ramsey-type phase control of free electron beams

    CERN Document Server

    Echternkamp, Katharina E; Schäfer, Sascha; Ropers, Claus

    2016-01-01

    Interference between multiple distinct paths is a defining property of quantum physics, where "paths" may involve actual physical trajectories, as in interferometry, or transitions between different internal (e.g. spin) states, or both. A hallmark of quantum coherent evolution is the possibility to interact with a system multiple times in a phase-preserving manner. This principle underpins powerful multi-dimensional optical and nuclear magnetic resonance spectroscopies and related techniques, including Ramsey's method of separated oscillatory fields used in atomic clocks. Previously established for atomic, molecular and quantum dot systems, recent developments in the optical quantum state preparation of free electron beams suggest a transfer of such concepts to the realm of ultrafast electron imaging and spectroscopy. Here, we demonstrate the sequential coherent interaction of free electron states with two spatially separated, phase-controlled optical near-fields. Ultrashort electron pulses are acted upon in ...

  19. Vanderbilt free electron laser project in biomedical and materials research

    Science.gov (United States)

    Haglund, Richard F.; Tolk, N. H.

    1988-06-01

    The Medical Free Electron Laser Program was awarded to develop, construct and operate a free-electron laser facility dedicated to biomedical and materials studies, with particular emphases on: fundamental studies of absorption and localization of electromagnetic energy on and near material surfaces, especially through electronic and other selective, non-statistical processes; non-thermal photon-materials interactions (e.g., electronic bond-breaking or vibrational energy transfer) in physical and biological materials as well as in long-wavelength biopolymer dynamics; development of FEL-based methods to study drug action and to characterize biomolecular properties and metabolic processes in biomembranes; clinical applications in otolaryngology, neurosurgery, ophthalmology and radiology stressing the use of the laser for selective laser-tissue, laser-cellular and laser-molecule interactions in both therapeutic and diagnostic modalities.

  20. Accelerator Technology Division progress report, FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  1. Physics of Superpulses in Storage Ring Free-Electron Lasers

    Directory of Open Access Journals (Sweden)

    Vladimir N. Litvinenko

    2008-01-01

    Full Text Available Contradictory to the widespread perception, storage ring free-electron lasers with substantial net gain can generate peak lasing power reaching GW levels in the so-called superpulse mode. This power level is sufficient for studies of nonlinear processes and efficient intracavity harmonic generation. This letter describes the physics of the superpulses and a phase-space refreshment in the electron beam responsible for this phenomenon.

  2. Free electron laser based on the Smith-Purcell radiation

    Institute of Scientific and Technical Information of China (English)

    WANG Ming-hong; XIAO Xiao-guang; YU Hui-shan; MENG Xian-zhu

    2006-01-01

    A Smith-Purcell (SP) free electron laser (FEL) ,composed of a metallic diffraction flat grating,an open cylindrical mirror cavity and a relativistic sheet electron beam with moderate energy, is presented. The characteristics of this device are studied by theoretical analysis, experimental measurements and particle-in-cell (PIC) simulation method. Results indicate that the coherent radiation with an output peak power up to 50 MW at millimeter wavelengths can be generated by using relativistic electron beam of moderate energy.

  3. Pair creation and an x-ray free electron laser.

    Science.gov (United States)

    Alkofer, R; Hecht, M B; Roberts, C D; Schmidt, S M; Vinnik, D V

    2001-11-05

    Using a quantum kinetic equation we study the possibility that focused beams at proposed x-ray free electron laser facilities can initiate spontaneous electron-positron pair production from the QED vacuum. Under conditions reckoned achievable at planned facilities, repeated cycles of particle creation and annihilation will take place in tune with the laser frequency. The peak particle number density is insensitive to this frequency, and one can anticipate the production of a few hundred particle pairs per laser period.

  4. Naval electric weapons the electromagnetic railgun and free electron laser

    OpenAIRE

    Williams, Robert E.

    2004-01-01

    Approved for public release; distribution is unlimited Theory and simulations of the railgun and free electron laser are presented, as well as a suggestion for extending the railgun lifecycle. The theory, design, and analysis of an electromagnetic railgun using a numerical model are discussed. The effects of varying electrical pulse formations, rail materials and geometries are explored. The application of a metallurgical process to mitigate hypervelocity gouging in railgun rails is propos...

  5. High Harmonic Inverse Free Electron Laser Interaction at 800 nm

    Energy Technology Data Exchange (ETDEWEB)

    Sears, C

    2005-03-08

    We demonstrate for the first time an inverse free electron laser (IFEL) operating at 800 nm and observe multiple resonances of the IFEL interaction. The IFEL is tested at half its fundamental resonance electron energy and scanned through multiple harmonics by adjusting the undulator field strength. We obtain a peak modulation of {approx}50 keV FWHM and observe the 4th through 6th harmonics of the IFEL resonance.

  6. An Efficient Microwave Power Source: Free-electron Laser Afterburner

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.; Sessler, Andrew M.

    1993-03-04

    A kind of microwave power source, called a free-electron laser afterburner (FEL afterburner) which consists of a free-electron laser buncher and a slow-wave output structure sharing a magnetic wiggler field with the buncher, is proposed. The buncher and the slow-wave structure can operate in either a travelling-wave state or a standing-wave state. In the buncher, the wiggler field together with the radiation field makes an electron beam bunched, and in the slow-wave structure the wiggler field keeps the beam bunched while the bunched beam interacts strongly with the slow-wave structure and so produces rf power. The bunching process comes from the free-electron laser mechanism and the generating process of rf power is in a slow-wave structure. A three-dimensional, time-dependent code is used to simulate a particular standing-wave FEL afterburner and it is shown that rf power of up to 1.57 GW can be obtained, at 17.12 GHz, from a l-kA, 5-MeV electron beam.

  7. High-brightness beamline for x-ray spectroscopy at the ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Jones, G. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (United States)

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard x-ray beamline, and its brightness will be an order of magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new {open_quotes}Cowan type{close_quotes} double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12 m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

  8. Compact stacking of diode lasers for pulsed light sources of high brightness.

    Science.gov (United States)

    Alahautala, Taito; Lassila, Erkki; Hernberg, Rolf

    2004-07-20

    A compact stacking architecture for high-power diode-laser arrays is proposed and compared with traditional stacks. The objective of compact stacking is to achieve high brightness values without the use of microlenses. The calculated brightness for a compact stack is over 300 W mm(-2) sr(-1), which is approximately 40 times higher than that of a traditional stack made of similar laser emitters. Even higher brightness values of over 600 W mm(-2) sr(-1) were reached in practice. A laser head was manufactured in which the light from several compact laser stacks could be fiber coupled or the light could be transformed to a highly uniform beam.

  9. High brightness beam shaping and fiber coupling of laser-diode bars.

    Science.gov (United States)

    Yu, Junhong; Guo, Linui; Wu, Hualing; Wang, Zhao; Tan, Hao; Gao, Songxin; Wu, Deyong; Zhang, Kai

    2015-04-10

    The strong beam quality mismatch in the fast and slow axes of laser-diode bars requires a significant beam shaping method to reach the parameters needed for fiber coupling. An effective solution to this problem is proposed that is based on a right-angle prism array and a distributed cylinder-lens stack. Coupling 12 mini-bars into a standard 100 μm core diameter and 0.15 numerical aperture fiber is achieved, and the output power can reach 400 W. Using this technique, production of compact and high brightness fiber-coupled laser-diode modules is possible.

  10. Report of the working group on production and dynamics of high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, R.L. [MS H851I, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Bisognano, J.; Brau, C.; Hogan, M.; Kim, K.; Milton, S.; Nuhn, H.; Pagani, C.; Pierini, P.; Reiser, M.; Schmerge, J.; Serafini, L.; Teng, L.; Winick, H.; Cornacchia, M.

    1997-02-01

    This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper: proposed new electron sources and needed research on existing sources, discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions, and the present status of the theoretical modeling of beam transport in bends. {copyright} {ital 1997 American Institute of Physics.}

  11. First results from the high-brightness x-ray spectroscopy beamline at ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Ng, W.; Jones, G. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology and x-ray optical development programs at ALS. X-ray absorption and time of flight photo emission measurements in 2 - 5 keV photon energy in argon along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

  12. Graded Heterojunction of AlGaInP High-brightness Light Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    LIU Lu; FAN Guang-han; LIAO Chang-jun

    2004-01-01

    A simple model of the graded heterojunction in AlGaInP compound semiconductors was introduced to analyze the band profile. The band profiles are analyzed with the different grading ways but the same grading length and under the different doping densities. The effect of the different grading lengths on the surplus of the potential of the spike to the potential of N region are also analyzed under the different doping densities.Through the experiments,it proves that the performances of high brightness light emitting diodes can be improved by the effects of the graded heterojunction.

  13. InGaN micro-LED-pillar as the building block for high brightness emitters

    KAUST Repository

    Shen, Chao

    2013-01-01

    In summary, we confirmed the improved electrical and optical characteristics, with reduced efficiency droop in InGaN μLED-pillars when these devices were scaled down in size. We demonstrated that strain relief contributed to further improvement in EQE characteristics in small InGaN μLED-pillars (D < 50 μm), apart from the current spreading effect. The μLED-pillar can be deployed as the building block for large effective-area, high brightness emitter. © 2013 IEEE.

  14. Deep Saturated Free Electron Laser Oscillators and Frozen Spikes

    CERN Document Server

    Ottaviani, P L; Dattoli, G; Sabia, E; Petrillo, V; Van Der Slot, P; Biedron, S; Milton, S

    2016-01-01

    We analyze the behavior of Free Electron Laser (FEL) oscillators operating in the deep saturated regime and point out the formation of sub-peaks of the optical pulse. They are very stable configurations, having a width corresponding to a coherence length. We speculate on the physical mechanisms underlying their growth and attempt an identification with FEL mode locked structures associated with Super Modes. Their impact on the intra-cavity nonlinear harmonic generation is also discussed along with the possibility of exploiting them as cavity out-coupler.

  15. Quantum regime of a free-electron laser: relativistic approach

    Science.gov (United States)

    Kling, Peter; Sauerbrey, Roland; Preiss, Paul; Giese, Enno; Endrich, Rainer; Schleich, Wolfgang P.

    2017-01-01

    In the quantum regime of the free-electron laser, the dynamics of the electrons is not governed by continuous trajectories but by discrete jumps in momentum. In this article, we rederive the two crucial conditions to enter this quantum regime: (1) a large quantum mechanical recoil of the electron caused by the scattering with the laser and the wiggler field and (2) a small energy spread of the electron beam. In contrast to our recent approach based on nonrelativistic quantum mechanics in a co-moving frame of reference, we now pursue a model in the laboratory frame employing relativistic quantum electrodynamics.

  16. Single-crystal phosphors for high-brightness white LEDs/LDs

    Science.gov (United States)

    Víllora, Encarnación G.; Arjoca, Stelian; Inomata, Daisuke; Shimamura, Kiyoshi

    2016-03-01

    White light-emitting diodes (wLEDs) are the new environmental friendly sources for general lighting purposes. For applications requiring a high-brightness, current wLEDs present overheating problems, which drastically decrease their emission efficiency, color quality and lifetime. This work gives an overview of the recent investigations on single-crystal phosphors (SCPs), which are proposed as novel alternative to conventional ceramic powder phosphors (CPPs). This totally new approach takes advantage of the superior properties of single-crystals in comparison with ceramic materials. SCPs exhibit an outstanding conversion efficiency and thermal stability up to 300°C. Furthermore, compared with encapsulated CPPs, SCPs possess a superior thermal conductivity, so that generated heat can be released efficiently. The conjunction of all these characteristics results in a low temperature rise of SCPs even under high blue irradiances, where conventional CPPs are overheated or even burned. Therefore, SCPs represent the ideal, long-demanded all-inorganic phosphors for high-brightness white light sources, especially those involving the use of high-density laser-diode beams.

  17. A novel high-brightness broadband light-source technology from the VUV to the IR

    Science.gov (United States)

    Horne, Stephen; Smith, Don; Besen, Matthew; Partlow, Matthew; Stolyarov, Daniil; Zhu, Huiling; Holber, William

    2010-04-01

    A novel technology has been developed which enables high-brightness, broadband light output from the VUV to the IR spectral regions. A focused laser is used to sustain a high-pressure xenon discharge inside a bulb, creating a smaller, hotter discharge than can be obtained by using an electrically-driven discharge. This allows for continuous output down to 120 nm wavelength and into the infrared. Application areas include hyperspectral imaging, standoff detection, surveillance, bioanalytical instrumentation, microscopy, and materials studies. Laser-driven optical discharges were first investigated over 30 years ago, providing the initial technical understanding of such discharges. However it took the convergence of two separate elements - the availability of low-cost, high-efficiency CW diode lasers; and a market need for high-brightness, broadband light source - to provide the impetus for further development in this area. Using near-IR CW diode lasers at power levels from 15 W to over 2000 W, we have generated high-pressure xenon discharges having temperatures as high as 10,000 C. The optical brightness of these discharges can be over an order of magnitude higher than those obtainable from the brightest xenon arc lamps, and can be several orders of magnitude brighter than deuterium lamps. Results from modeling of these discharges as well as experimental measurements will be presented.

  18. Longitudinal phase space manipulation in energy recovering linac-driven free-electron lasers

    Directory of Open Access Journals (Sweden)

    P. Piot

    2003-03-01

    Full Text Available Energy recovering an electron beam after it has participated in a free-electron laser (FEL interaction can be quite challenging because of the substantial FEL-induced energy spread and the energy antidamping that occurs during deceleration. In the Jefferson Lab infrared FEL driver accelerator, such an energy recovery scheme was implemented by properly matching the longitudinal phase space throughout the recirculation transport by employing the so-called energy compression scheme. In the present paper, after presenting a single-particle dynamics approach of the method used to energy recover the electron beam, we report on experimental validation of the method obtained by measurements of the so-called “compression efficiency” and “momentum compaction” lattice transfer maps at different locations in the recirculation transport line. We also compare these measurements with numerical tracking simulations.

  19. High Power Electron Beam Injectors for 100 kW Free Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Todd, Alan; Bluem, Hans; Christina, Vincent; Cole, Michael; Rathke, John; Schultheiss, Tom; Colestock, Patrick; Kelley, J.P.; Kurennoy, Sergey; Nguyen, Dung; Russell, S.; Schrage, Dale; Wood, R.L.; Young, L.M.; Campisi, Isidoro; Daly, Edward; Douglas, David; Neil, George; Preble, Joseph; Rimmer, Robert; Rode, Claus; Sekutowicz, Jacek; Whitlatch, Timothy; Wiseman, Mark

    2003-05-01

    A key technology issue on the path to high-power FEL operation is the demonstration of reliable, highbrightness, high-power injector operation. We describe two ongoing programs to produce 100 mA injectors as drivers for 100 kW free-electron lasers. In one approach, in collaboration with the Thomas Jefferson National Accelerator Facility, we are fabricating a 750 MHz superconducting RF cryomodule that will be integrated with a room-temperature DC photocathode gun [1] and tested at the Laboratory. In the other approach, in collaboration with Los Alamos National Laboratory, a high-current 700 MHz, normal-conducting, RF photoinjector [2,3] is being designed and will undergo thermal management testing at the Laboratory. We describe the design, the projected performance and the status of both injectors.

  20. High Harmonic Inverse Free-Electron-Laser Interaction at 800 NM

    CERN Document Server

    Sears, Chris M S; Colby, Eric R; Cowan, Benjamin; Plettner, Tomas; Siemann, Robert; Spencer, James

    2005-01-01

    The inverse Free Electron Laser (IFEL) interaction has recently been proposed and used as a short wavelength modulator forμbunching of beams for laser acceleration experiments*,**. These experiments utilized the fundamental of the interaction between the laser field and electron bunch. In the current experiment, we explore the higher order resonances of the IFEL interaction from a 3 period, 1.8 centimeter wavelength undulator with a picosecond, 0.25 mJ/pulse laser at 800 nm. The resonances are observed by adjusting the gap of the undulator while keeping the beam energy constant. We will also discuss diagnostics for obtaining beam overlap and statistical techniques used to account for machine drifts and analyze the data.

  1. First lasing of a high-gain harmonic generation free- electron laser experiment

    CERN Document Server

    Yu, L H; Ben-Zvi, I; Di Mauro, Louis F; Doyuran, A; Graves, W; Johnson, E; Krinsky, S; Malone, R; Pogorelsky, I V; Skaritka, J; Rakowsky, G; Solomon, L; Wang, X J; Woodle, M; Yakimenko, V; Biedron, S G; Galayda, J N; Gluskin, E; Jagger, J; Sajaev, Vadim; Vasserman, I

    2000-01-01

    We report on the first lasing of a high-gain harmonic generation (HGHG) free-electron laser (FEL). The experiment was conducted at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). This is a BNL experiment in collaboration with the Advanced Photon Source (APS) at Argonne National Laboratory. A preliminary measurement gives a high-gain harmonic generation (HGHG) pulse energy that is 2x10 sup 7 times larger than the spontaneous radiation. In a purely self-amplified spontaneous emission (SASE) mode of operation, the signal was measured as 10 times larger than the spontaneous radiation in the same distance (approx 2 m) through the same wiggler. This means the HGHG signal is 2x10 sup 6 times larger than the SASE signal. To obtain the same saturated output power by the SASE process, the radiator would have to be 3 times longer (6 m).

  2. High Harmonic Inverse Free-Electron-Laser Interaction at 800nm

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Christopher M.S.; Colby, Eric; Cowan, Ben; Siemann, Robert H.; Spencer, James; /SLAC; Byer, Robert L.; Plettner, Tomas; /Stanford U., Phys. Dept.

    2005-05-13

    The inverse Free Electron Laser (IFEL) interaction has recently been proposed and used as a short wavelength modulator for micro bunching of beams for laser acceleration experiments [1,2]. These experiments utilized the fundamental of the interaction between the laser field and electron bunch. In the current experiment, we explore the higher order resonances of the IFEL interaction from a 3 period, 1.8 centimeter wavelength undulator with a picosecond, 0.5 mJ/pulse laser at 800nm. The resonances are observed by adjusting the gap of the undulator while keeping the beam energy constant. We also compare the experimental results to a simple analytic model that describes coupling to high order harmonics of the interaction.

  3. High-Harmonic Inverse Free-Electron-Laser Interaction at 800nm

    Energy Technology Data Exchange (ETDEWEB)

    Sears, C

    2006-02-17

    The inverse Free Electron Laser (IFEL) interaction has recently been proposed and used as a short wavelength modulator for micro bunching of beams for laser acceleration experiments [1,2]. These experiments utilized the fundamental of the interaction between the laser field and electron bunch. In the current experiment, we explore the higher order resonances of the IFEL interaction from a 3 period, 1.8 centimeter wavelength undulator with a picosecond, 0.5 mJ/pulse laser at 800nm. The resonances are observed by adjusting the gap of the undulator while keeping the beam energy constant. We also compare the experimental results to a simple analytic model that describes coupling to high order harmonics of the interaction.

  4. Influence of an imperfect energy profile on a seeded free electron laser performance

    Directory of Open Access Journals (Sweden)

    Botao Jia

    2010-06-01

    Full Text Available A single-pass high-gain x-ray free electron laser (FEL calls for a high quality electron bunch. In particular, for a seeded FEL amplifier and for a harmonic generation FEL, the electron bunch initial energy profile uniformity is crucial for generating an FEL with a narrow bandwidth. After the acceleration, compression, and transportation, the electron bunch energy profile entering the undulator can acquire temporal nonuniformity. We study the influence of the electron bunch initial energy profile nonuniformity on the FEL performance. Intrinsically, for a harmonic generation FEL, the harmonic generation FEL in the final radiator starts with an electron bunch having energy modulation acquired in the previous stages, due to the FEL interaction at those FEL wavelengths and their harmonics. The influence of this electron bunch energy nonuniformity on the harmonic generation FEL in the final radiator is then studied.

  5. CAS on Free-Electron Lasers and Energy Recovery Linacs in Hamburg

    CERN Multimedia

    CERN Accelerator School

    2016-01-01

    The CERN Accelerator School (CAS) and DESY held a jointly-organised specialised course on Free-Electron Lasers and Energy Recovery Linacs (FELs and ERLs) in Hamburg, Germany, from 31 May to 10 June 2016.      The course was held in the Hotel Scandic Emporio in Hamburg and was attended by 68 participants of 13 nationalities, coming from countries as far away as China, Iran and Japan. The intensive programme comprised 44 lectures and one seminar. Following introductory lectures on electromagnetism, relativity and synchrotron radiation issues, the basic requirements of linacs and ERLs were discussed. Detailed lectures on the theory of FEL science followed. Undulators and the process of lasing and seeding were covered in some detail along with lectures on various beam dynamics and beam control issues. Case studies, for which seven hours were allocated, completed the academic programme. For these, the students were divided into small groups and tasked with completing the basic desig...

  6. MAGNETIC MODELING VS MEASUREMENTS OF THE DIPOLES FOR THE JLAB 10 KW FREE ELECTRON LASER UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    David Douglas; Robin Wines; Tom Hiatt; George Biallas; Kenneth Baggett; T.J. Schultheiss; V.A. Christina; J.W. Rathke; A. Smirnov; D. Newsham; Y. Luo; D. Yu

    2003-05-01

    Magnetic measurements of the six families of dipoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (Jlab) are compared to the magnetic models on which their design is based. The magnets were designed in parallel by three organizations. They used ANSYS, Radia or Opera 3D as a 3D magnetic modeling program. Comparison of the discrepancies between model and magnet measurement is presented along with analysis of their potential causes. These dipoles operate in two field ranges. The Injector/ Extractor Dipoles operate around 0.05 T and the Arc Dipoles and Optical Chicane Dipoles operate between 0.22 to 0.71 T. All magnets are required to meet core field and field integral flatness to parts in 104 over their good field region.

  7. Free electron lifetime achievements in Liquid Argon Imaging TPC

    CERN Document Server

    Baibussinov, B; Calligarich, E; Centro, S; Cieslik, K; Farnese, C; Fava, A; Gibin, D; Guglielmi, A; Meng, G; Pietropaolo, F; Rubbia, C; Varanini, F; Ventura, S

    2010-01-01

    A key feature for the success of the Liquid Argon TPC technology is the industrial purification against electro-negative impurities, especially Oxygen and Nitrogen remnants, which have to be initially and continuously kept at an exceptional purity. New purification techniques have been applied to a 120 litres LAr-TPC test facility in the INFN-LNL laboratory. Through-going muon tracks have been used to monitor the LAr purity. The short path length used (30 cm) is compensated by the high accuracy in the observation of the specific ionization of cosmic rays muons at sea level. A free electron lifetime of (21.4+7.3-4.3) ms, namely > 15.8 ms at 90 % C.L. has been observed under stable conditions over several weeks, corresponding to about 15 ppt (part per trillion) of Oxygen equivalent. At 500 V/cm, where the electron speed is approximately of 1.5 mm/us, the free electron lifetime >15 ms corresponds to an attenuation <15 % for a drift path of 5 m, opening the way to reliable operation of LAr TPC for exceptionall...

  8. Materials Research with the Vanderbilt Free-Electron Laser

    Science.gov (United States)

    Tolk, Norman

    1997-11-01

    The Vanderbilt Free-Electron Laser's (FEL) tunability (2-10=B5m), high intensity (15 MW) and short pulse structure (1 ps) make it ideal for studying (a) the electronic and vibrational structure of small and wide band gap semiconductors, and (b) non-thermal wavelength-selective materials alteration (``Free-Electron Laser Wavelength-Selective Materials Alteration and Photoexcitation Spectroscopy,'' N.H. Tolk, R.G. Albridge, A.V. Barnes, B.M. Barnes, J.L. Davidson, V.D. Gordon, G. Margaritondo, J.T. McKinley, G.A. Mensing, and J. Sturmann, Appl. Surf. Sci. 106, 205-210 (1996).). Two-photon absorption measurements in Ge were the first verification of a two-decades old predictionby Bassani and Hassan that the indirect two-photon absorption in Ge would be an LO-phonon assisted process. The FEL has greatly facilitated internal photoemission (IPE) heterojunction band discontinuity measurements. This technique is a photocurrent excitation spectroscopy that provides a direct measurement of the discontinuity without resorting to complex modeling. Another important area of materials research at the FEL concerns identification of wavelength-selective mechanisms for materials alteration. We have used the FEL to demonstrate strongly wavelength-selective ablation near the C-H stretch vibrational mode in chemical vapor deposited (CVD) diamond.

  9. Bunch decompression for laser-plasma driven free-electron laser demonstration schemes

    Directory of Open Access Journals (Sweden)

    T. Seggebrock

    2013-07-01

    Full Text Available X-ray free-electron lasers (FELs require a very high electron beam quality in terms of emittance and energy spread. Since 2004 high quality electrons produced by laser-wakefield accelerators have been demonstrated, but the electron quality up to now did not allow the operation of a compact x-ray FEL using these electrons. Maier et al. [Phys. Rev. X 2, 031019 (2012PRXHAE2160-330810.1103/PhysRevX.2.031019] suggested a concept for a proof-of-principle experiment allowing FEL operation in the vacuum ultraviolet range based on an optimized undulator and bunch decompression using electron bunches from a laser-plasma accelerator as currently available. In this paper we discuss in more detail how a chicane can be used as a bunch stretcher instead of a bunch compressor to allow the operation of a laser-wakefield accelerator driven FEL using currently available electrons. A scaling characterizing the impact of bunch decompression on the gain length is derived and the feasibility of the concept is tested numerically in a demanding scenario.

  10. Studies on a VUV free electron laser at the TESLA Test Facility at DESY

    Energy Technology Data Exchange (ETDEWEB)

    Rossbach, J. [Deutsches Elektronen-Synchrotron, Hamburg (Germany)

    1995-12-31

    The TESLA Test Facility (TTF) currently under construction at DESY is a test-bed for acceleration sections of a high-gradient, high efficiency superconducting linear collider. Due to ist unrivaled ability to sustain high beam quality during acceleration, a superconducting rf linac is considered the optimum choice to drive a Free Electron Laser (FEL). We aim at a photon wavelength of {lambda} = 6 manometer utilizing the TTF after is has been extended to 1 GeV beam energy. Due to lack of mirrors and seed-lasers in this wavelength regime, a single pass FEL and Self-Amplified-Spontaneous-Emission (SASE) is considered. A first test is foreseen at a larger photon wavelength. The overall design as well as both electron and photon beam properties will be discussed. To reach the desired photon wavelength, the main components that have to be added to the TTF are: (a) a low emittance rf gun including space charge compensation (b) a two stage bunch compressor increasing the peak bunch current from 100 A up to 2500 A (c) four more accelerating modules to achieve 1 GeV beam energy (d) a 25 m long undulator (period length 27 mm, peak field 0.5 T) The average brillance will be larger than 1-10{sup 22}photons/s/mm{sup 2}/mrad{sup 2}/0.1%. Each 800 {mu}s long pulse will contain up to 7200 equidistant bunches. The repetition frequency of the linac is 10 Hz.

  11. A study on materials of steels by high brightness X-ray

    CERN Document Server

    Tsuzaki, K; Umezawa, O; Hara, T; Takahashi, T; Omura, T; Hayakawa, M; Yamauchi, Y

    2001-01-01

    As the survey study on materials analysis of steels using high brightness X-ray, under aiming to clarify direct experimental facts on deformations, failure phenomena, and metal textures forming at interior portions of bulk materials, feasibility on materials research and development using SPring-8 was surveyed. Its concrete items were summarized to fields shown as follows: 1) acquirement of foundation on synchrotron X-ray, 2) visualization of cracks and artificial cracks in metal bulk samples by using refraction imaging (point light source topography), 3) visualization of the second phase in the metal bulk samples by using refraction imaging, and 4) speciation of carbon elements in steel cords by Moessbauer spectroscopy. Together with clarifying problems more and more by the survey and some experiments, subjects and understandings vacantly considered at standpoints of materials researchers could be arranged and defined. (G.K.)

  12. High brightness MEMS mirror based head-up display (HUD) modules with wireless data streaming capability

    Science.gov (United States)

    Milanovic, Veljko; Kasturi, Abhishek; Hachtel, Volker

    2015-02-01

    A high brightness Head-Up Display (HUD) module was demonstrated with a fast, dual-axis MEMS mirror that displays vector images and text, utilizing its ~8kHz bandwidth on both axes. Two methodologies were evaluated: in one, the mirror steers a laser at wide angles of phone applications is demonstrated, utilizing the mobile device both for content generation based on various messages or data, and for content streaming to the MEMS controller via Bluetooth interface. The display unit is highly resistant to vibrations and shock, and requires only ~1.5W to operate, even with content readable in sunlit outdoor conditions. The low power requirement is in part due to a vector graphics approach, allowing the efficient use of laser power, and also due to the use of a single, relatively high efficiency laser and simple optics.

  13. Designing and optimizing highly efficient grating for high-brightness laser based on spectral beam combining

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying-Ying, E-mail: xclin@semi.ac.cn, E-mail: yangyy@semi.ac.cn; Zhao, Ya-Ping; Wang, Li-Rong; Zhang, Ling; Lin, Xue-Chun, E-mail: xclin@semi.ac.cn, E-mail: yangyy@semi.ac.cn [Laboratory of All Solid State Light Sources, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2015-03-14

    A highly efficient nano-periodical grating is theoretically investigated for spectral beam combining (SBC) and is experimentally implemented for attaining high-brightness laser from a diode laser array. The rigorous coupled-wave analysis with the S matrix method is employed to optimize the parameters of the grating. According the optimized parameters, the grating is fabricated and plays a key role in SBC cavity. The diffraction efficiency of this grating is optimized to 95% for the output laser which is emitted from the diode laser array. The beam parameter product of 3.8 mm mrad of the diode laser array after SBC is achieved at the output power of 46.3 W. The optical-to-optical efficiency of SBC cavity is measured to be 93.5% at the maximum operating current in the experiment.

  14. Femtosecond laser pumped by high-brightness coherent polarization locked diodes.

    Science.gov (United States)

    Purnawirman; Phua, P B

    2011-08-01

    We demonstrate, for the first time to our knowledge, the use of a coherent polarization locked diode as the high-brightness pump source for a femtosecond laser. Four diode emitters are coherently locked to produce more than 5 W linearly polarized, narrow linewidth, and single-lobed pump beam. This gives >10× brightness improvement over the conventional diode array. The diode beam is then used to pump a Yb:KYW laser to obtain 2 W output with 57% slope efficiency in cw laser operation. By using a saturable absorber mirror, we achieved cw mode-locking operation with a 177 fs pulse width at an average power of 0.55 W.

  15. Spectrotemporal shaping of seeded free-electron laser pulses.

    Science.gov (United States)

    Gauthier, David; Ribič, Primož Rebernik; De Ninno, Giovanni; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Bojanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca; Mahieu, Benoît; Penco, Giuseppe

    2015-09-11

    We demonstrate the ability to control and shape the spectrotemporal content of extreme-ultraviolet (XUV) pulses produced by a seeded free-electron laser (FEL). The control over the spectrotemporal properties of XUV light was achieved by precisely manipulating the linear frequency chirp of the seed laser. Our results agree with existing theory, which allows us to retrieve the temporal properties (amplitude and phase) of the FEL pulse from measurements of the spectra as a function of the FEL operating parameters. Furthermore, we show the first direct evidence of the full temporal coherence of FEL light and generate Fourier limited pulses by fine-tuning the FEL temporal phase. The possibility of tailoring the spectrotemporal content of intense short-wavelength pulses represents the first step towards efficient nonlinear optics in the XUV to x-ray spectral region and will enable precise manipulation of core-electron excitations using the methods of coherent quantum control.

  16. Charge transfer to ground-state ions produces free electrons

    Science.gov (United States)

    You, D.; Fukuzawa, H.; Sakakibara, Y.; Takanashi, T.; Ito, Y.; Maliyar, G. G.; Motomura, K.; Nagaya, K.; Nishiyama, T.; Asa, K.; Sato, Y.; Saito, N.; Oura, M.; Schöffler, M.; Kastirke, G.; Hergenhahn, U.; Stumpf, V.; Gokhberg, K.; Kuleff, A. I.; Cederbaum, L. S.; Ueda, K.

    2017-01-01

    Inner-shell ionization of an isolated atom typically leads to Auger decay. In an environment, for example, a liquid or a van der Waals bonded system, this process will be modified, and becomes part of a complex cascade of relaxation steps. Understanding these steps is important, as they determine the production of slow electrons and singly charged radicals, the most abundant products in radiation chemistry. In this communication, we present experimental evidence for a so-far unobserved, but potentially very important step in such relaxation cascades: Multiply charged ionic states after Auger decay may partially be neutralized by electron transfer, simultaneously evoking the creation of a low-energy free electron (electron transfer-mediated decay). This process is effective even after Auger decay into the dicationic ground state. In our experiment, we observe the decay of Ne2+ produced after Ne 1s photoionization in Ne-Kr mixed clusters.

  17. Spin-polarizing interferometric beam splitter for free electrons

    CERN Document Server

    Dellweg, Matthias M

    2016-01-01

    A spin-polarizing electron beam splitter is described which relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity. An incident electron beam is first coherently scattered off a bichromatic laser field, splitting the beam into two portions, with electron spin and momentum being entangled. Afterwards, the partial beams are coherently superposed in an interferometric setup formed by standing laser waves. As a result, the outgoing electron beam is separated into its spin components along the laser magnetic field, which is shown by both analytical and numerical solutions of Pauli's equation. The proposed laser field configuration thus exerts the same effect on free electrons like an ordinary Stern-Gerlach magnet does on atoms.

  18. Raman free-electron laser with a coaxial wiggler

    Science.gov (United States)

    Farokhi, B.; Maraghechi, B.; Willett, J. E.

    2000-10-01

    A one-dimensional theory of the stimulated Raman scattering mechanism for a coaxial free-electron laser (FEL) is developed. The beam-frame FEL dispersion relation and a formula for the lab-frame spatial growth rate are derived. A numerical study of the growth rate for the coaxial wiggler is made and compared with that for the helical wiggler. Except for a part of the group II orbits, the growth rate is found to be less than the helical wiggler. Relativistic effects due to the transverse oscillation of electrons in the wiggler field prevent the FEL operation from approaching magnetoresonance. In the absence of these relativistic mass effects, the calculations show a magnetoresonance associated with the first spatial harmonic and a much narrower resonance at the third spatial harmonic.

  19. Medical free-electron laser: fact or fiction?

    Science.gov (United States)

    Bell, James P.; Ponikvar, Donald R.

    1994-07-01

    The free electron laser (FEL) has long been proposed as a flexible tool for a variety of medical applications, and yet the FEL has not seen widespread acceptance in the medical community. The issues have been the laser's size, cost, and complexity. Unfortunately, research on applications of FELs has outpaced the device development efforts. This paper describes the characteristics of the FEL, as they have been demonstrated in the U.S. Army's FEL technology development program, and identifies specific medical applications where demonstrated performance levels would suffice. This includes new photodynamic therapies for cancer and HIV treatment, orthopedic applications, tissue welding applications, and multiwavelength surgical techniques. A new tunable kilowatt class FEL device is described, which utilizes existing hardware from the U.S. Army program. An assessment of the future potential, based on realistic technology scaling is provided.

  20. Resurrection of beam conditioning for free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ming

    2003-02-17

    Recently Emma and Stupakov identified a fatal flaw in a Free Electron Laser (FEL) beam conditioning scheme. They showed that the conditioning is always accompanied by a projected transverse emittance growth that is so large as to make the beam conditioning completely impractical for short wavelength FELs. Furthermore, they provided a general proof along with evidence of computer simulation and reached a conclusion that any beam conditioner, regardless of the method, would suffer from the same constraints and limitations. In this paper, the author proposes an easy surgical removal of the fatal flaw by making a critical yet simple modification to the very scheme analyzed, thus resurrect the beam conditioning for short wavelength FELs. More generally, the also explain why a general search for removing have failed, why the concept and definition of beam conditioning.

  1. Charge transfer to ground-state ions produces free electrons

    Science.gov (United States)

    You, D.; Fukuzawa, H.; Sakakibara, Y.; Takanashi, T.; Ito, Y.; Maliyar, G. G.; Motomura, K.; Nagaya, K.; Nishiyama, T.; Asa, K.; Sato, Y.; Saito, N.; Oura, M.; Schöffler, M.; Kastirke, G.; Hergenhahn, U.; Stumpf, V.; Gokhberg, K.; Kuleff, A. I.; Cederbaum, L. S.; Ueda, K

    2017-01-01

    Inner-shell ionization of an isolated atom typically leads to Auger decay. In an environment, for example, a liquid or a van der Waals bonded system, this process will be modified, and becomes part of a complex cascade of relaxation steps. Understanding these steps is important, as they determine the production of slow electrons and singly charged radicals, the most abundant products in radiation chemistry. In this communication, we present experimental evidence for a so-far unobserved, but potentially very important step in such relaxation cascades: Multiply charged ionic states after Auger decay may partially be neutralized by electron transfer, simultaneously evoking the creation of a low-energy free electron (electron transfer-mediated decay). This process is effective even after Auger decay into the dicationic ground state. In our experiment, we observe the decay of Ne2+ produced after Ne 1s photoionization in Ne–Kr mixed clusters. PMID:28134238

  2. Čerenkov free-electron laser with side walls

    Science.gov (United States)

    Kalkal, Yashvir; Kumar, Vinit

    2016-08-01

    In this paper, we have proposed a Čerenkov free-electron laser (CFEL) with metallic side walls, which are used to confine an electromagnetic surface mode supported by a thin dielectric slab placed on top of a conducting surface. This leads to an enhancement in coupling between the optical mode and the co-propagating electron beam, and consequently, performance of the CFEL is improved. We set up coupled Maxwell-Lorentz equations for the system, in analogy with an undulator based conventional FEL, and obtain formulas for the small-signal gain and growth rate. It is shown that small signal gain and growth rate in this configuration are larger compared to the configuration without the side walls. In the nonlinear regime, we solve the coupled Maxwell-Lorentz equations numerically and study the saturation behaviour of the system. It is found that the Čerenkov FEL with side walls saturates quickly, and produces powerful coherent terahertz radiation.

  3. Čerenkov free-electron laser with side walls

    Energy Technology Data Exchange (ETDEWEB)

    Kalkal, Yashvir, E-mail: yashvirkalkal@gmail.com [Homi Bhabha National Institute, Mumbai 400094 (India); Accelerator and Beam Physics Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Kumar, Vinit [Homi Bhabha National Institute, Mumbai 400094 (India); Accelerator and Beam Physics Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

    2016-08-11

    In this paper, we have proposed a Čerenkov free-electron laser (CFEL) with metallic side walls, which are used to confine an electromagnetic surface mode supported by a thin dielectric slab placed on top of a conducting surface. This leads to an enhancement in coupling between the optical mode and the co-propagating electron beam, and consequently, performance of the CFEL is improved. We set up coupled Maxwell–Lorentz equations for the system, in analogy with an undulator based conventional FEL, and obtain formulas for the small-signal gain and growth rate. It is shown that small signal gain and growth rate in this configuration are larger compared to the configuration without the side walls. In the nonlinear regime, we solve the coupled Maxwell–Lorentz equations numerically and study the saturation behaviour of the system. It is found that the Čerenkov FEL with side walls saturates quickly, and produces powerful coherent terahertz radiation.

  4. Observation of Hanbury Brown-Twiss anticorrelations for free electrons.

    Science.gov (United States)

    Kiesel, Harald; Renz, Andreas; Hasselbach, Franz

    2002-07-25

    Fluctuations in the counting rate of photons originating from uncorrelated point sources become, within the coherently illuminated area, slightly enhanced compared to a random sequence of classical particles. This phenomenon, known in astronomy as the Hanbury Brown-Twiss effect, is a consequence of quantum interference between two indistinguishable photons and Bose Einstein statistics. The latter require that the composite bosonic wavefunction is a symmetric superposition of the two possible paths. For fermions, the corresponding two-particle wavefunction is antisymmetric: this excludes overlapping wave trains, which are forbidden by the Pauli exclusion principle. Here we use an electron field emitter to coherently illuminate two detectors, and find anticorrelations in the arrival times of the free electrons. The particle beam has low degeneracy (about 10(-4) electrons per cell in phase space); as such, our experiment represents the fermionic twin of the Hanbury Brown-Twiss effect for photons.

  5. Imaging the dynamics of free-electron Landau states.

    Science.gov (United States)

    Schattschneider, P; Schachinger, Th; Stöger-Pollach, M; Löffler, S; Steiger-Thirsfeld, A; Bliokh, K Y; Nori, Franco

    2014-08-08

    Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions.

  6. On harmonic operation of Shanghai deep UV free electron laser

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By choosing parameters in the modulator,the dispersive section and the seed laser,the spatial bunching of the electron beam can be correlated to then-th harmonic of ther adiator radiation,instead of the fundamental radiation in conventional high-gain harmonic generation(HGHG).Thus,the radiator undulator is operated at high harmonic mode.In this paper,the possibility of harmonic operation of Shanghai deep ultraviolet(SDUV)free electron laser (FEL)is studied.Discussions on the principle of harmonic operation,the simulation code development,the simulation results.and the proposed experimental procedure for verification of harmonic operation at the SDUV FEL are also presented.

  7. Limitations of electron beam conditioning for free-electron lasers

    Directory of Open Access Journals (Sweden)

    P. Emma

    2003-03-01

    Full Text Available Several ideas have been proposed to “condition” an electron beam prior to the undulator of a free-electron laser (FEL by increasing each particle’s energy in proportion to the square of its transverse betatron amplitude. This conditioning enhances FEL gain by reducing the axial velocity spread within the electron bunch. We demonstrate that for symplectic beam lines, and independent of the method, this conditioning is always accompanied by a large head-tail focusing variation which, for short-wavelength FELs, is so severe as to make conditioning completely impractical. We furthermore find that any system added to correct the head-tail focusing variation will also remove the conditioning. As an example, a new method for conditioning is presented and shown to generate exactly the same head-tail focusing problems as in previously published work.

  8. Free electron lasers with slowly varying beam and undulator parameters

    Directory of Open Access Journals (Sweden)

    Z. Huang

    2005-04-01

    Full Text Available A self-consistent theory of a free electron laser (FEL with slowly varying beam and undulator parameters is developed using the WKB approximation. The theory is applied to study the performance of a self-amplified spontaneous emission (SASE FEL when the electron beam energy varies along the undulator as would be caused by vacuum pipe wakefields and/or when the undulator strength parameter is tapered in the small signal regime before FEL saturation. We find that a small energy gain or an equivalent undulator taper slightly reduces the power gain length in the exponential growth regime and can increase the saturated SASE power by about a factor of 2. Power degradation away from the optimal performance can be estimated based upon knowledge of the SASE bandwidth. The analytical results, which agree with numerical simulations, are used to optimize the undulator taper and to evaluate wakefield effects.

  9. Optical klystron and harmonic generation free electron laser

    Directory of Open Access Journals (Sweden)

    Qika Jia

    2005-06-01

    Full Text Available The optical field evolution of an optical klystron free electron laser is analytically described for both low gain and high gain cases. The harmonic optical klystron (HOK in which the second undulator is resonant on the higher harmonic of the first undulator is analyzed as a harmonic amplifier. The optical field evolution equation of the HOK is derived analytically for both the CHG mode (coherent harmonic generation, the quadratic gain regime and the HGHG mode (high gain harmonic generation, the exponential gain regime, the effects of energy spread, energy modulation, and dispersion in the whole process are taken into account. The linear theory is given and discussed for the HGHG mode. The analytical formula is given for the CHG mode.

  10. Gain of harmonic generation in high gain free electron laser

    Institute of Scientific and Technical Information of China (English)

    DENG Hai-Xiao; DAI Zhi-Min

    2008-01-01

    In a planar undulator employed free electron laser(FEL),each harmonic radiation starts from linear amplification and ends with nonlinear harmonic interactions of the lower nonlinear harmonics and the fundamental radiation.In this paper,we investigate the harmonic generation based on the dispersion relation driven from the coupled Maxwell-Vlasov equations,taking into account the effects due to energy spread,emittance,betatron oscillation of electron beam as well as diffraction guiding of the radiation field.A 3D universal scaling function for gain of the linear harmonic generation and a 1D universal scaling function for gain of the nonlinear harmonic generation are presented,which promise rapid computation in FEL design and optimization.The analytical approaches have been validated by 3D simulation results in large range.

  11. Research on the high-brightness traffic variable message sign based on laser diodes

    Science.gov (United States)

    Feng, Li-li; Huang, Hai-tao; Ruan, Chi

    2015-10-01

    Researches indicate that foggy weather is one of the most critical factors that restrict human's traffic activities and cause traffic accidents. It will reduce the visibility of traffic message board, which could cause the insecurity of transportation. Commonly, light-emitting diodes (LEDs) were used as light source for variable message sign, which could not be seen clearly in the foggy low visibility condition. A high-brightness light source which could be used for variable information board was firstly put forward in this paper. And a new type of variable message sign used in low visibility condition was also introduced. Besides, the attenuation characteristics of laser diode (LD) and light-emitting diode (LED) were analyzed respectively. Calculation and simulation show that the attenuation of red light source is fastest, and the yellow LED light has the better transmittance property. In the experiment, LDs were used to make variable message board for verifying image definition. A 16*16 array structure composed of LDs was designed and could display Chinese characters. By comparing the display effect of LDs and LEDs driven with same power, they were placed in fog chamber of the visibility less than 5 meters. And experiment results show that the penetrability of red LD light is better than that of red LED. So traffic variable message sign based on LDs could improve the image definition and the information could be seen more clearly in the foggy weather. In addition to the high-brightness, good coherence, good direction, experimental results show that traffic variable message board based on LD has better visual effect in low visibility condition.

  12. New high-brightness monochrome monitor based on color CRT technology

    Science.gov (United States)

    Spekowius, Gerhard; Weibrecht, Martin; D'Adda, Carlo; Antonini, Antonio; Casale, Carlo; Blume, Hartwig R.

    1997-05-01

    With increasing availability of medical image communication infrastructures, medical images are more and more displayed as soft-copies rather than as hard-copies. Often however, the image viewing environment is characterized by high ambient light, such as in surgery rooms or offices illuminated by daylight. We are describing a very-high- brightness cathode-ray-tube (CRT) monitor which accommodates these viewing conditions without the typical deterioration in resolution due to electron focal spot blooming. The three guns of a standard color CRT are used to create a high brightness monochrome monitor. The CRT has no shadow-mask, and a homogeneous P45 phosphor layer has been deposited instead of the structured red-green-blue color phosphor screen. The electron spots of the three guns are dynamically matched by applying appropriate waveforms to four additional multiple magnetic fields around the gun assembly. We evaluated the image quality of the triple-gun CRT monitor concerning parameters which are especially relevant for medical imaging applications. We have measured characteristic curves, dynamic range, veiling glare, resolution, spot profiles, and screen noise. The monitor can provide a high luminance of more than 200 fL. Due to nearly perfect matching of the three spots, the resolution is mainly determined by the beam profile of a single gun and is remarkably high even at these high luminance values. The P45 phosphor shows very little structure noise, which is an advantage for medical desktop applications. Since all relevant monitor parameters are digitally controlled, the status of the monitor can be fully characterized at any time. This feature particularly facilitates the reproduction of brightness and contrast values and hence allows easy implementation of a display function standard or to return to a desired display function that has been found useful for a given application in the past.

  13. Four-wave-mixing experiments with seeded free electron lasers.

    Science.gov (United States)

    Bencivenga, F; Calvi, A; Capotondi, F; Cucini, R; Mincigrucci, R; Simoncig, A; Manfredda, M; Pedersoli, E; Principi, E; Dallari, F; Duncan, R A; Izzo, M G; Knopp, G; Maznev, A A; Monaco, G; Di Mitri, S; Gessini, A; Giannessi, L; Mahne, N; Nikolov, I P; Passuello, R; Raimondi, L; Zangrando, M; Masciovecchio, C

    2016-12-16

    The development of free electron laser (FEL) sources has provided an unprecedented bridge between the scientific communities working with ultrafast lasers and extreme ultraviolet (XUV) and X-ray radiation. Indeed, in recent years an increasing number of FEL-based applications have exploited methods and concepts typical of advanced optical approaches. In this context, we recently used a seeded FEL to demonstrate a four-wave-mixing (FWM) process stimulated by coherent XUV radiation, namely the XUV transient grating (X-TG). We hereby report on X-TG measurements carried out on a sample of silicon nitride (Si3N4). The recorded data bears evidence for two distinct signal decay mechanisms: one occurring on a sub-ps timescale and one following slower dynamics extending throughout and beyond the probed timescale range (100 ps). The latter is compatible with a slower relaxation (time decay > ns), that may be interpreted as the signature of thermal diffusion modes. From the peak intensity of the X-TG signal we could estimate a value of the effective third-order susceptibility which is substantially larger than that found in SiO2, so far the only sample with available X-TG data. Furthermore, the intensity of the time-coincidence peak shows a linear dependence on the intensity of the three input beams, indicating that the measurements were performed in the weak field regime. However, the timescale of the ultrafast relaxation exhibits a dependence on the intensity of the XUV radiation. We interpreted the observed behaviour as the generation of a population grating of free-electrons and holes that, on the sub-ps timescale, relaxes to generate lattice excitations. The background free detection inherent to the X-TG approach allowed the determination of FEL-induced electron dynamics with a sensitivity largely exceeding that of transient reflectivity and transmissivity measurements, usually employed for this purpose.

  14. SASE自由电子激光%SASE free-electron lasers

    Institute of Scientific and Technical Information of China (English)

    张令翊; 庄杰佳; 赵夔; 陈佳洱

    2001-01-01

    SASE自由电子激光可以产生短至0.1nm的高亮度(峰值亮度比当前的第三代同步辐射高10个量级;平均亮度高3~5个量级)、短脉冲(脉冲长度小于2个量级,达到亚皮秒水平)硬X射线相干光。因而被称为是继第三代同步辐射之后的第四代光源。SASE依据的是高增益自由电子激光原理,利用了光阴极微波电子枪技术和电子直线加速器技术。综述了SASE的历史发展、基本原理、基本结构、主要物理特征和对电子束的要求。%As the fourth generation light source hard X-ray SASE free-electron laser has many unique properties superior to the 3rd synchrotron radiation: higher brightness (ten orders of magnitude of peak spectral bribhteness and three~five orders of magnitude of average brightness greater than the 3rd synchrotron radiation currently acjhieved), shorter pulse (two orders of magnitude of pulse duration shorter than the 3rd synchrotron radiation, down to sub-picosecond), shorter wavelength down to 0.1nm etc.. SASE is based on the principle of high gain free electron lasers, and technologies of photoinjector and linear accelerator. The development history of SASE, the basic theory, the typical configuration, the main physical characteristics and the requirements for electron beam is described.

  15. 5 (Upgradable to 25 keV) Free Electron Laser (FEL) Facility

    CERN Document Server

    York, R C

    2013-01-01

    A Free Electron Laser (FEL) facility utilizing a recirculated Superconducting Radio Frequency (SRF) linear accelerator (linac) provides the opportunity to achieve about five times greater photon energy than an unrecirculated linac of similar cost. > A 4 GeV SRF, cw, electron linac can be used to drive an FEL producing 5 keV photons. The SLAC National Accelerator Laboratory, a Department of Energy (DOE) Basic Energy Sciences (BES) laboratory, proposes to utilize a 4 GeV unrecirculated, SRF, linac in a segment of existing linac tunnel. > For an initial investment similar to that of the proposed SLAC strategy, a recirculated SRF linac system could deliver the 4 GeV electrons for photon energies of 5 keV and provide an upgrade path to photon energies of 25 keV. > Further support amounting to about a third of the initial investment would provide upgrade funds for additional SRF linac and cryogenic capacity sufficient to provide electron energies appropriate for 25 keV photons matching the European XFEL.

  16. X-band rf driven free electron laser driver with optics linearization

    Directory of Open Access Journals (Sweden)

    Yipeng Sun (孙一鹏

    2014-11-01

    Full Text Available In this paper, a compact hard X-ray free electron lasers (FEL design is proposed with all X-band rf acceleration and two stage bunch compression. It eliminates the need of a harmonic rf linearization section by employing optics linearization in its first stage bunch compression. Quadrupoles and sextupoles are employed in a bunch compressor one (BC1 design, in such a way that second order longitudinal dispersion of BC1 cancels the second order energy correlation in the electron beam. Start-to-end 6-D simulations are performed with all the collective effects included. Emittance growth in the horizontal plane due to coherent synchrotron radiation is investigated and minimized, to be on a similar level with the successfully operating Linac coherent light source (LCLS. At a FEL radiation wavelength of 0.15 nm, a saturation length of 40 meters can be achieved by employing an undulator with a period of 1.5 cm. Without tapering, a FEL radiation power above 10 GW is achieved with a photon pulse length of 50 fs, which is LCLS-like performance. The overall length of the accelerator plus undulator is around 250 meters which is much shorter than the LCLS length of 1230 meters. That makes it possible to build hard X-ray FEL in a laboratory with limited size.

  17. Membrane protein structural biology using X-ray free electron lasers.

    Science.gov (United States)

    Neutze, Richard; Brändén, Gisela; Schertler, Gebhard F X

    2015-08-01

    Membrane protein structural biology has benefitted tremendously from access to micro-focus crystallography at synchrotron radiation sources. X-ray free electron lasers (XFELs) are linear accelerator driven X-ray sources that deliver a jump in peak X-ray brilliance of nine orders of magnitude and represent a disruptive technology with potential to dramatically change the field. Membrane proteins were amongst the first macromolecules to be studied with XFEL radiation and include proof-of-principle demonstrations of serial femtosecond crystallography (SFX), the observation that XFEL data can deliver damage free crystallographic structures, initial experiments towards recording structural information from 2D arrays of membrane proteins, and time-resolved SFX, time-resolved wide angle X-ray scattering and time-resolved X-ray emission spectroscopy studies. Conversely, serial crystallography methods are now being applied using synchrotron radiation. We believe that a context dependent choice of synchrotron or XFEL radiation will accelerate progress towards novel insights in understanding membrane protein structure and dynamics.

  18. Accelerator Technology Division annual report, FY 1989

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This paper discusses: accelerator physics and special projects; experiments and injectors; magnetic optics and beam diagnostics; accelerator design and engineering; radio-frequency technology; accelerator theory and simulation; free-electron laser technology; accelerator controls and automation; and high power microwave sources and effects.

  19. The Free-Electron-Laser user facility FELIX

    Science.gov (United States)

    Oepts, D.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1995-01-01

    The Free Electron Laser for Infrared eXperiments FELIX presents to its users a versatile source of radiation in the infrared and far-infrared spectral regions. Presently, the wavelength range of operation extends from 5 to 110 μm (2000-90 cm -1). The wavelength is continuously tunable over an octave in a few minutes. The output normally consists of macropulses of 5-10 μs duration, formed by a train of micropulses of a few ps length. Average power in the macropulses is of order 10 kW, peak power in the micropulses is in the MW range. The temporal and spectral characteristics of the micropulses can be controlled by varying the synchronism between the electron pulses and the optical pulses circulating in the laser cavity. Transform-limited pulse lengths in the range 2-20 ps can be generated. Long-range coherence has been induced by phase-locking successive micropulses, and narrow-band, essentially single-mode, radiation has been selected from the output.

  20. Optical guiding and beam bending in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Scharlemann, E.T.

    1987-01-01

    The electron beam in a free-electron laser (FEL) can act as an optical fiber, guiding or bending the optical beam. The refractive and gain effects of the bunched electron beam can compensate for diffraction, making possible wigglers that are many Rayleigh ranges (i.e., characteristic diffraction lengths) long. The origin of optical guiding can be understood by examining gain and refractive guiding in a fiber with a complex index of refraction, providing a mathematical description applicable also to the FEL, with some extensions. In the exponential gain regime of the FEL, the electron equations of motion must be included, but a self-consistent description of exponential gain with diffraction fully included becomes possible. The origin of the effective index of refraction of an FEL is illustrated with a simple example of bunched, radiating dipoles. Some of the properties of the index of refraction are described. The limited experimental evidence for optical beam bending is summarized. The evidence does not yet provide conclusive proof of the existence of optical guiding, but supports the idea. Finally, the importance of refractive guiding for the performance of a high-gain tapered-wiggler FEL amplifier is illustrated with numerical simulations.

  1. European X-Ray Free Electron Laser (EXFEL): local implications

    Science.gov (United States)

    Romaniuk, Ryszard S.

    2013-10-01

    European X-Ray FEL - free electron laser is under construction in DESY Hamburg. It is scheduled to be operational at 2015/16 at a cost more than 1 billion Euro. The laser uses SASE method to generate x-ray light. It is propelled by an electron linac of 17,5GeV energy and more than 2km in length. The linac uses superconducting SRF TESLA technology working at 1,3 GHz in frequency. The prototype of EXFEL is FLASH Laser (200 m in length), where the "proof of principle" was checked, and from the technologies were transferred to the bigger machine. The project was stared in the nineties by building a TTF Laboratory -Tesla Test Facility. The EXFEL laser is a child of a much bigger teraelectronovolt collider project TESLA (now abandoned in Germany but undertaken by international community in a form the ILC). A number of experts and young researchers from Poland participate in the design, construction and research of the FLASH and EXFEL lasers.

  2. Structural enzymology using X-ray free electron lasers.

    Science.gov (United States)

    Kupitz, Christopher; Olmos, Jose L; Holl, Mark; Tremblay, Lee; Pande, Kanupriya; Pandey, Suraj; Oberthür, Dominik; Hunter, Mark; Liang, Mengning; Aquila, Andrew; Tenboer, Jason; Calvey, George; Katz, Andrea; Chen, Yujie; Wiedorn, Max O; Knoska, Juraj; Meents, Alke; Majriani, Valerio; Norwood, Tyler; Poudyal, Ishwor; Grant, Thomas; Miller, Mitchell D; Xu, Weijun; Tolstikova, Aleksandra; Morgan, Andrew; Metz, Markus; Martin-Garcia, Jose M; Zook, James D; Roy-Chowdhury, Shatabdi; Coe, Jesse; Nagaratnam, Nirupa; Meza, Domingo; Fromme, Raimund; Basu, Shibom; Frank, Matthias; White, Thomas; Barty, Anton; Bajt, Sasa; Yefanov, Oleksandr; Chapman, Henry N; Zatsepin, Nadia; Nelson, Garrett; Weierstall, Uwe; Spence, John; Schwander, Peter; Pollack, Lois; Fromme, Petra; Ourmazd, Abbas; Phillips, George N; Schmidt, Marius

    2017-07-01

    Mix-and-inject serial crystallography (MISC) is a technique designed to image enzyme catalyzed reactions in which small protein crystals are mixed with a substrate just prior to being probed by an X-ray pulse. This approach offers several advantages over flow cell studies. It provides (i) room temperature structures at near atomic resolution, (ii) time resolution ranging from microseconds to seconds, and (iii) convenient reaction initiation. It outruns radiation damage by using femtosecond X-ray pulses allowing damage and chemistry to be separated. Here, we demonstrate that MISC is feasible at an X-ray free electron laser by studying the reaction of M. tuberculosis ß-lactamase microcrystals with ceftriaxone antibiotic solution. Electron density maps of the apo-ß-lactamase and of the ceftriaxone bound form were obtained at 2.8 Å and 2.4 Å resolution, respectively. These results pave the way to study cyclic and non-cyclic reactions and represent a new field of time-resolved structural dynamics for numerous substrate-triggered biological reactions.

  3. Optical Shaping of X-Ray Free-Electron Lasers

    Science.gov (United States)

    Marinelli, A.; Coffee, R.; Vetter, S.; Hering, P.; West, G. N.; Gilevich, S.; Lutman, A. A.; Li, S.; Maxwell, T.; Galayda, J.; Fry, A.; Huang, Z.

    2016-06-01

    In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes.

  4. LIPSS Free-Electron Laser Searches for Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-01

    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.

  5. Model-based optimization of tapered free-electron lasers

    Directory of Open Access Journals (Sweden)

    Alan Mak

    2015-04-01

    Full Text Available The energy extraction efficiency is a figure of merit for a free-electron laser (FEL. It can be enhanced by the technique of undulator tapering, which enables the sustained growth of radiation power beyond the initial saturation point. In the development of a single-pass x-ray FEL, it is important to exploit the full potential of this technique and optimize the taper profile a_{w}(z. Our approach to the optimization is based on the theoretical model by Kroll, Morton, and Rosenbluth, whereby the taper profile a_{w}(z is not a predetermined function (such as linear or exponential but is determined by the physics of a resonant particle. For further enhancement of the energy extraction efficiency, we propose a modification to the model, which involves manipulations of the resonant particle’s phase. Using the numerical simulation code GENESIS, we apply our model-based optimization methods to a case of the future FEL at the MAX IV Laboratory (Lund, Sweden, as well as a case of the LCLS-II facility (Stanford, USA.

  6. Extreme-Ultraviolet Vortices from a Free-Electron Laser

    Directory of Open Access Journals (Sweden)

    Primož Rebernik Ribič

    2017-08-01

    Full Text Available Extreme-ultraviolet vortices may be exploited to steer the magnetic properties of nanoparticles, increase the resolution in microscopy, and gain insight into local symmetry and chirality of a material; they might even be used to increase the bandwidth in long-distance space communications. However, in contrast to the generation of vortex beams in the infrared and visible spectral regions, production of intense, extreme-ultraviolet and x-ray optical vortices still remains a challenge. Here, we present an in-situ and an ex-situ technique for generating intense, femtosecond, coherent optical vortices at a free-electron laser in the extreme ultraviolet. The first method takes advantage of nonlinear harmonic generation in a helical undulator, producing vortex beams at the second harmonic without the need for additional optical elements, while the latter one relies on the use of a spiral zone plate to generate a focused, micron-size optical vortex with a peak intensity approaching 10^{14}  W/cm^{2}, paving the way to nonlinear optical experiments with vortex beams at short wavelengths.

  7. Modeling and multidimensional optimization of a tapered free electron laser

    Directory of Open Access Journals (Sweden)

    Y. Jiao

    2012-05-01

    Full Text Available Energy extraction efficiency of a free electron laser (FEL can be greatly increased using a tapered undulator and self-seeding. However, the extraction rate is limited by various effects that eventually lead to saturation of the peak intensity and power. To better understand these effects, we develop a model extending the Kroll-Morton-Rosenbluth, one-dimensional theory to include the physics of diffraction, optical guiding, and radially resolved particle trapping. The predictions of the model agree well with that of the GENESIS single-frequency numerical simulations. In particular, we discuss the evolution of the electron-radiation interaction along the tapered undulator and show that the decreasing of refractive guiding is the major cause of the efficiency reduction, particle detrapping, and then saturation of the radiation power. With this understanding, we develop a multidimensional optimization scheme based on GENESIS simulations to increase the energy extraction efficiency via an improved taper profile and variation in electron beam radius. We present optimization results for hard x-ray tapered FELs, and the dependence of the maximum extractable radiation power on various parameters of the initial electron beam, radiation field, and the undulator system. We also study the effect of the sideband growth in a tapered FEL. Such growth induces increased particle detrapping and thus decreased refractive guiding that together strongly limit the overall energy extraction efficiency.

  8. Numerical Simulations of X-Ray Free Electron Lasers (XFEL)

    KAUST Repository

    Antonelli, Paolo

    2014-11-04

    We study a nonlinear Schrödinger equation which arises as an effective single particle model in X-ray free electron lasers (XFEL). This equation appears as a first principles model for the beam-matter interactions that would take place in an XFEL molecular imaging experiment in [A. Fratalocchi and G. Ruocco, Phys. Rev. Lett., 106 (2011), 105504]. Since XFEL are more powerful by several orders of magnitude than more conventional lasers, the systematic investigation of many of the standard assumptions and approximations has attracted increased attention. In this model the electrons move under a rapidly oscillating electromagnetic field, and the convergence of the problem to an effective time-averaged one is examined. We use an operator splitting pseudospectral method to investigate numerically the behavior of the model versus that of its time-averaged version in complex situations, namely the energy subcritical/mass supercritical case and in the presence of a periodic lattice. We find the time-averaged model to be an effective approximation, even close to blowup, for fast enough oscillations of the external field. This work extends previous analytical results for simpler cases [P. Antonelli, A. Athanassoulis, H. Hajaiej, and P. Markowich, Arch. Ration. Mech. Anal., 211 (2014), pp. 711--732].

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2011-01-20

    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.

  10. Determining contrast sensitivity functions for monochromatic light emitted by high-brightness LEDs

    Science.gov (United States)

    Ramamurthy, Vasudha; Narendran, Nadarajah; Freyssinier, Jean Paul; Raghavan, Ramesh; Boyce, Peter

    2004-01-01

    Light-emitting diode (LED) technology is becoming the choice for many lighting applications that require monochromatic light. However, one potential problem with LED-based lighting systems is uneven luminance patterns. Having a uniform luminance distribution is more important in some applications. One example where LEDs are becoming a viable alternative and luminance uniformity is an important criterion is backlighted monochromatic signage. The question is how much uniformity is required for these applications. Presently, there is no accepted metric that quantifies luminance uniformity. A recent publication proposed a method based on digital image analysis to quantify beam quality of reflectorized halogen lamps. To be able to employ such a technique to analyze colored beams generated by LED systems, it is necessary to have contrast sensitivity functions (CSFs) for monochromatic light produced by LEDs. Several factors including the luminance, visual field size, and spectral power distribution of the light affect the CSFs. Although CSFs exist for a variety of light sources at visual fields ranging from 2 degrees to 20 degrees, CSFs do not exist for red, green, and blue light produced by high-brightness LEDs at 2-degree and 10-degree visual fields and at luminances typical for backlighted signage. Therefore, the goal of the study was to develop a family of CSFs for 2-degree and 10-degree visual fields illuminated by narrow-band LEDs at typical luminances seen in backlighted signs. The details of the experiment and the results are presented in this manuscript.

  11. Compact high brightness diode laser emitting 500W from a 100μm fiber

    Science.gov (United States)

    Heinemann, Stefan; Fritsche, Haro; Kruschke, Bastian; Schmidt, Torsten; Gries, Wolfgang

    2013-02-01

    High power, high brightness diode lasers are beginning to compete with solid state lasers, i.e. disk and fiber lasers. The core technologies for brightness scaling of diode lasers are optical stacking and dense spectral combining (DSC), as well as improvements of the diode material. Diode lasers have the lowest cost of ownership, highest efficiency and most compact design among all lasers. Multiple Single Emitter (MSE) modules allow highest power and highest brightness diode lasers based on standard broad area diodes. Multiple single emitters, each rated at 12 W, are stacked in the fast axis with a monolithic slow axis collimator (SAC) array. Volume Bragg Gratings (VBG) stabilizes the wavelength and narrow the linewidth to less than 1 nm. Dichroic mirrors are used for dense wavelength multiplexing of 4 channels within 12 nm. Subsequently polarization multiplexing generates 450 W with a beam quality of 4.5 mm*mrad. Fast control electronics and miniaturized switched power supplies enable pulse rise times of less than 10 μs, with pulse widths continuously adjustable from 20 μs to cw. Further power scaling up to multi-kilowatts can be achieved by multiplexing up to 16 channels. The power and brightness of these systems enables the use of direct diode lasers for cutting and welding. The technologies can be transferred to other wavelengths to include 793 nm and 1530 nm. Optimized spectral combining enables further improvements in spectral brightness and power.

  12. Quantum emitters coupled to circular nanoantennas for high-brightness quantum light sources

    Science.gov (United States)

    Abudayyeh, Hamza A.; Rapaport, Ronen

    2017-09-01

    Engineering the directionality and emission rate of quantum light sources is essential in the development of modern quantum applications. In this work we use numerical calculations to optimise the brightness of a broadband quantum emitter positioned in a hybrid metal-dielectric circular periodic nanoantenna. The optimised structure features a photon collection efficiency of 74 % (82 % ) and a photon flux enhancement of over 10 (6) into a numerical aperture of 0.22 (0.50), respectively, corresponding to a direct coupling into two types of multi-mode fibres. To enhance the emission rate, we present a new circular nanoantenna design where a quantum emitter is attached to a silver nanocone at the centre of the antenna. After optimisation, we find a collection efficiency of 61 % (78 % ) into a numerical aperture of 0.22 (0.50), giving a brightness enhancement of 1000 (600) for an unpolarised emitter. The enhancements in both structures are broadband due to the low-quality factor of the device and are therefore ideal for room-temperature sources. This type of a scalable design can be utilised towards on-chip, high-brightness quantum light sources operating at room temperature.

  13. Droplet-based, high-brightness extreme ultraviolet laser plasma source for metrology

    Science.gov (United States)

    Vinokhodov, A. Yu.; Krivokorytov, M. S.; Sidelnikov, Yu. V.; Krivtsun, V. M.; Medvedev, V. V.; Koshelev, K. N.

    2016-10-01

    We report on the development of a high brightness source of extreme ultraviolet radiation (EUV) with a working wavelength of 13.5 nm. The source is based on a laser-produced plasma driven by pulsed radiation of a Nd:YAG laser system. Liquid droplets of Sn-In eutectic alloy were used as the source fuel. The droplets were created by a droplet generator operating in the jet break-up regime. The EUV emission properties of the plasma, including the emission spectrum, time profile, and conversion efficiency of laser radiation into useful 13.5 nm photons, have been characterized. Using the shadowgraphy technique, we demonstrated the production of corpuscular debris by the plasma source and the influence of the plasma on the neighboring droplet targets. The high-frequency laser operation was simulated by usage of the dual pulse regime. Based on the experimental results, we discuss the physical phenomena that could affect the source operation at high repetition rates. Finally, we estimate that an average source brightness of 1.2 kW/mm2 sr is feasible at a high repetition rate.

  14. Generation and propagation of high-brightness electron beams from a magnetically crowbarred injector

    Science.gov (United States)

    Humphries, S., Jr.; Len, L. K.; Allen, C. B.

    1987-05-01

    Tests of a 300-keV electrostatic electron beam injector with a magnetic crowbar switch are described. The saturable ferrite core switch allows generation of a constant voltage, 80-ns pulse directly from a Marx generator. Inductive isolation in the switch permits direct access to the high-voltage electrode for thermionic or active plasma cathode experiments. The pulse modulator can drive a 1.5-kA load. A high brightness 290-A beam from a felt plasma-emission cathode was extracted and propagated in vacuum. Because of the reliability of the magnetic crowbar switch, more than 500 shots were accumulated on the cathode at over 1 kA/sq cm with no degradation of the output. The output beam had a normalized brightness of 2.6 x 10 to the 8th A/(m rad) sq. A solenoidal lens was used to match the space-charge-dominated beam into a 1-m-long periodic focusing system with 25 reversing solenoidal coils. A beam current of 150 A was successfully transported through the 1.7-cm radius tube.

  15. Stable droplet generator for a high brightness laser produced plasma extreme ultraviolet source

    Science.gov (United States)

    Vinokhodov, A.; Krivokorytov, M.; Sidelnikov, Yu.; Krivtsun, V.; Medvedev, V.; Bushuev, V.; Koshelev, K.; Glushkov, D.; Ellwi, S.

    2016-10-01

    We present the results of the low-melting liquid metal droplets generation based on excited Rayleigh jet breakup. We discuss on the operation of the industrial and in-house designed and manufactured dispensing devices for the droplets generation. Droplet diameter can be varied in the range of 30-90 μm. The working frequency of the droplets, velocity, and the operating temperature were in the ranges of 20-150 kHz, 4-15 m/s, and up to 250 °C, respectively. The standard deviations for the droplet center of mass position both their diameter σ < 1 μm at the distance of 45 mm from the nozzle. Stable operation in the long-term (over 1.5 h) was demonstrated for a wide range of the droplet parameters: diameters, frequencies, and velocities. Physical factors affecting the stability of the generator operation have been identified. The technique for droplet synchronization, allowing using the droplet as a target for laser produced plasma, has been created; in particular, the generator has been successfully used in a high brightness extreme ultraviolet (EUV) light source. The operation with frequency up to 8 kHz was demonstrated as a result of the experimental simulation, which can provide an average brightness of the EUV source up to ˜1.2 kW/mm2 sr.

  16. Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Anatoly Shteynberg, PhD

    2006-08-17

    This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

  17. Strain relief InGaN/GaN MQW micro-pillars for high brightness LEDs

    KAUST Repository

    Shen, Chao

    2013-01-01

    Micro-structured group-III-nitrides are considered as promising strain relief structures for high efficiency solid state lighting. In this work, the strain field in InGaN/GaN multi-quantum wells (MQWs) micro-pillars is investigated using micro-Raman spectroscopy and the design of micro-pillars were studied experimentally. We distinguished the strained and strain-relieved signatures of the GaN layer from the E2 phonon peak split from the Raman scattering signatures at 572 cm-1 and 568 cm-1, respectively. The extent of strain relief is examined considering the height and size of micro-pillars fabricated using focused ion beam (FIB) micro-machining technique. A significant strain relief can be achieved when one micro-machined through the entire epi-layers, 3 μm in our study. The dependence of strain relief on micro-pillar diameter (D) suggested that micro-pillar with D < 3 μm showed high degree of strain relief. Our results shed new insights into designing strain-relieved InGaN/GaN microstructures for high brightness light emitting diode arrays. © 2013 IEEE.

  18. Free-electron lasers: Echoes of photons past

    Science.gov (United States)

    Campbell, Lawrence T.; McNeil, Brian W. J.

    2016-08-01

    High-harmonic generation is an established method to significantly upshift laser photon energies. Now, researchers at the SLAC National Accelerator Laboratory have used echo concepts to generate coherent high-harmonic output from an electron-beam light source.

  19. Detailed characterization of electron sources yielding first demonstration of European X-ray Free-Electron Laser beam quality

    Directory of Open Access Journals (Sweden)

    F. Stephan

    2010-02-01

    Full Text Available The photoinjector test facility at DESY, Zeuthen site (PITZ, was built to develop and optimize photoelectron sources for superconducting linacs for high-brilliance, short-wavelength free-electron laser (FEL applications like the free-electron laser in Hamburg (FLASH and the European x-ray free-electron laser (XFEL. In this paper, the detailed characterization of two laser-driven rf guns with different operating conditions is described. One experimental optimization of the beam parameters was performed at an accelerating gradient of about 43  MV/m at the photocathode and the other at about 60  MV/m. In both cases, electron beams with very high phase-space density have been demonstrated at a bunch charge of 1 nC and are compared with corresponding simulations. The rf gun optimized for the lower gradient has surpassed all the FLASH requirements on beam quality and rf parameters (gradient, rf pulse length, repetition rate and serves as a spare gun for this facility. The rf gun studied with increased accelerating gradient at the cathode produced beams with even higher brightness, yielding the first demonstration of the beam quality required for driving the European XFEL: The geometric mean of the normalized projected rms emittance in the two transverse directions was measured to be 1.26±0.13  mm mrad for a 1-nC electron bunch. When a 10% charge cut is applied excluding electrons from those phase-space regions where the measured phase-space density is below a certain level and which are not expected to contribute to the lasing process, the normalized projected rms emittance is about 0.9 mm mrad.

  20. Studies of harmonic generation in free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Goldammer, K.

    2007-11-12

    Nonlinear harmonic generation is one of the most interesting aspects of Free Electron Lasers under study today. It provides for coherent, high intensity radiation at higher harmonics of the FEL resonant frequency. The sources, numerical simulation and applications of harmonic radiation in cascaded High Gain Harmonic Generation FELs were the subject of this thesis. Harmonic emission in FELs originates from harmonic microbunching of the particles and the particular electron trajectory during FEL interaction. Numerical FEL simulation codes model these analytical equations and predict the performance of Free Electron Lasers with good accuracy. This thesis has relied heavily upon the FEL simulation code Genesis 1.3 which has been upgraded in the framework of this thesis to compute harmonic generation in a self-consistent manner. Tests against analytical predictions suggest that the harmonic power levels as well as harmonic gain lengths are simulated correctly. A benchmark with the FEL simulation code GINGER yields excellent agreement of the harmonic saturation length and saturation power. The new version of the simulation code Genesis was also tested against measurements from the VUV-FEL FLASH at DESY. The spectral power distributions of fundamental and third harmonic radiation were recorded at 25.9 nm and 8.6 nm, respectively. The relative bandwidths (FWHM) were in the range of 2 % for both the fundamental as well as the third harmonic, which was accurately reproduced by time-dependent simulations with Genesis. The new code was also used to propose and evaluate a new design for the BESSY Soft X-Ray FEL, a cascaded High Gain Harmonic Generation FEL proposed by BESSY in Berlin. The original design for the BESSY High Energy FEL line requires four HGHG stages to convert the initial seed laser wavelength of 297.5 nm down to 1.24 nm. A new scheme is proposed that makes use of fifth harmonic radiation from the first stage and reduces the number of HGHG stages to three. It

  1. Nonlinear resonances in a multi-stage free-electron laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, S. [Graduate Univ. for Advanced Studies, Ibaraki-ken (Japan); Takayama, K. [National Lab. for High Energy Physics, Ibaraki-ken (Japan)

    1995-12-31

    A two-beam accelerator (TBA) is a possible candidate of future linear colliders, in which the demanded rf power is provided by a multi-stage free-electron laser (MFEL). After if amplification in each stage, a driving beam is re-accelerated by an induction unit and propagates into the next stage. Recently it has been recognized that the multi-stage character of the MFEL causes resonances between its periodicity and the synchrotron motion in an rf bucket. Since the synchrotron oscillation is strongly modulated by the resonance and at the worst a large fraction of particles is trapped in the resonance islands, the nonlinear resonances in the FEL longitudinal beam dynamics can lead to notable degradation of the MFEL performance, such as output fluctuation and phase modulation which have been big concerns in the accelerator society. The overall efficiency of the MFEL and the quality of the amplified microwave power are key issues for realizing the TBA/FEL Particularly the rf phase and amplitude errors must be maintained within tolerance. One of significant obstacles is an amplification of undesired modes. If a small-size waveguide is employed, the FEL resonance energies for undesired higher order modes shift very far from that for a fundamental mode; so it is possible to prevent higher order modes from evolving. Such a small-size waveguide, however, gives a high power density in the FEL. Simulation results have demonstrated that the nonlinear resonances occur in die FEL longitudinal motion when the power density exceeds some threshold. An analytical method for studying the nonlinear resonance in the TBA/FEL is developed based on the macroparticle model which can describe analytically the drastic behaviors in the evolutions of the phase and amplitude. In the theory the basic 1D-FEL equations are reduced to a nonlinear pendulum equation with respect to the ponderomotive phase.

  2. Design and experimental tests of free electron laser wire scanners

    Science.gov (United States)

    Orlandi, G. L.; Heimgartner, P.; Ischebeck, R.; Loch, C. Ozkan; Trovati, S.; Valitutti, P.; Schlott, V.; Ferianis, M.; Penco, G.

    2016-09-01

    SwissFEL is a x-rays free electron laser (FEL) driven by a 5.8 GeV linac under construction at Paul Scherrer Institut. In SwissFEL, wire scanners (WSCs) will be complementary to view-screens for emittance measurements and routinely used to monitor the transverse profile of the electron beam during FEL operations. The SwissFEL WSC is composed of an in-vacuum beam-probe—motorized by a stepper motor—and an out-vacuum pick-up of the wire signal. The mechanical stability of the WSC in-vacuum hardware has been characterized on a test bench. In particular, the motor induced vibrations of the wire have been measured and mapped for different motor speeds. Electron-beam tests of the entire WSC setup together with different wire materials have been carried out at the 250 MeV SwissFEL Injector Test Facility (SITF, Paul Scherrer Institut, CH) and at FERMI (Elettra-Sincrotrone Trieste, Italy). In particular, a comparative study of the relative measurement accuracy and the radiation-dose release of Al (99 )∶Si (1 ) and tungsten (W) wires has been carried out. On the basis of the outcome of the bench and electron-beam tests, the SwissFEL WSC can be qualified as a high resolution and machine-saving diagnostic tool in consideration of the mechanical stability of the scanning wire at the micrometer level and the choice of the wire material ensuring a drastic reduction of the radiation-dose release with respect to conventional metallic wires. The main aspects of the design, laboratory characterization and electron beam tests of the SwissFEL WSCs are presented.

  3. High efficiency, multiterawatt x-ray free electron lasers

    Directory of Open Access Journals (Sweden)

    C. Emma

    2016-02-01

    Full Text Available In this paper we present undulator magnet tapering methods for obtaining high efficiency and multiterawatt peak powers in x-ray free electron lasers (XFELs, a key requirement for enabling 3D atomic resolution single molecule imaging and nonlinear x-ray science. The peak power and efficiency of tapered XFELs is sensitive to time dependent effects, like synchrotron sideband growth. To analyze this dependence in detail we perform a comparative numerical optimization for the undulator magnetic field tapering profile including and intentionally disabling these effects. We show that the solution for the magnetic field taper profile obtained from time independent optimization does not yield the highest extraction efficiency when time dependent effects are included. Our comparative optimization is performed for a novel undulator designed specifically to obtain TW power x-ray pulses in the shortest distance: superconducting, helical, with short period and built-in strong focusing. This design reduces the length of the breaks between modules, decreasing diffraction effects, and allows using a stronger transverse electron focusing. Both effects reduce the gain length and the overall undulator length. We determine that after a fully time dependent optimization of a 100 m long Linac coherent light source-like XFEL we can obtain a maximum efficiency of 7%, corresponding to 3.7 TW peak radiation power. Possible methods to suppress the synchrotron sidebands, and further enhance the FEL peak power, up to about 6 TW by increasing the seed power and reducing the electron beam energy spread, are also discussed.

  4. Hybrid planar free-electron maser in the magnetoresonance regime

    Directory of Open Access Journals (Sweden)

    Vitaliy A. Goryashko

    2009-10-01

    Full Text Available We study the operation regime of a hybrid planar free-electron maser (FEM amplifier near the magnetoresonant value of the uniform longitudinal (guide magnetic field. Using analytical expressions for individual test electron trajectories and normal frequencies of their three-dimensional oscillations in the magnetostatic field of the hybrid planar FEM, an analytical condition of chaotization of motion is established and shown to be given by the Chirikov resonance-overlap criterion applied to the normal undulator and cyclotron frequencies with respect to the coupling induced by the undulator magnetic field. It is also shown analytically that, in spite of the well-known drop for the exact magnetoresonance, the gain attains its maximal value in the zone of regular dynamics slightly above the magnetoresonant value of the guide magnetic field. Under the condition of undulator resonance, it is practically independent of the amplitude of the undulator magnetic field and the wavelength of amplified signal. To account for space-charge effects, we propose a theoretical model of a weakly relativistic FEM, which accommodates not only potential but also rotational parts of the nonradiated electromagnetic field of a moving charged particle. It turns out that the rotational part of nonradiated field diminishes the defocusing influence of the potential part on the beam bunching. Numeric simulation of the nonlinear stage of amplification is fulfilled, taking into consideration adiabatic entrance of the electron beam to the interaction region and initial electron velocity spread. We find that nonradiated field and initial electron velocity spread do not influence essentially the efficiency of hybrid planar FEM amplification if parameters of the beam-microwave interaction correspond to the operational regime in the zone of regular dynamics near the magnetoresonance.

  5. Pulse-by-pulse multi-beam-line operation for x-ray free-electron lasers

    Directory of Open Access Journals (Sweden)

    Toru Hara

    2016-02-01

    Full Text Available The parallel operation of plural undulator beam lines is an important means of improving the efficiency and usability of x-ray free-electron laser facilities. After the installation of a second undulator beam line (BL2 at SPring-8 Angstrom compact free-electron laser (SACLA, pulse-by-pulse switching between two beam lines was tested using kicker and dc twin-septum magnets. To maintain a compact size, all undulator beam lines at SACLA are designed to be placed within the same undulator hall located downstream of the accelerator. In order to ensure broad tunability of the laser wavelength, the electron bunches are accelerated to different beam energies optimized for the wavelengths of each beam line. In the demonstration, the 30 Hz electron beam was alternately deflected to two beam lines and simultaneous lasing was achieved with 15 Hz at each beam line. Since the electron beam was deflected twice by 3° in a dogleg to BL2, the coherent synchrotron radiation (CSR effects became non-negligible. Currently in a wavelength range of 4–10 keV, a laser pulse energy of 100–150  μJ can be obtained with a reduced peak current of around 1 kA by alleviating the CSR effects. This paper reports the results and operational issues related to the multi-beam-line operation of SACLA.

  6. Development of a High- Brightness, Quasi- Monoenergetic Neutron Source at LLNL for Nuclear Physics Applications

    Science.gov (United States)

    Johnson, M. S.; Anderson, S. G.; Bleuel, D.; Fitsos, P. J.; Gibson, D.; Hall, J. M.; Marsh, R.; Rusnak, B.

    2016-09-01

    Lawrence Livermore National Laboratory is developing a high-brightness, quasi-monoenergetic neutron source. The intensity of the neutron source is expected to be 1011 n/s/sr with energies between 7 MeV and 10 MeV at 5% bandwidth at 0-degrees. This energy region is important for the study of neutron-induced reactions, nuclear astrophysics, and nuclear structure. For example, for neutrons between 1 and 10 MeV, the capturing states are below the GDR in many nuclei and the dominant reactions are compound and direct capture. The intensity and energy selection of the source makes it appealing for measurements of sparse targets at specific energies. We will present an array of nuclear physics measurements that will benefit from this source. The source is also of interest to generating activated targets for decay-out studies or for target production for other reaction-based measurements, e.g. fusion-evaporation reactions. Other usage examples include practical applications for imaging of very dense objects such as machine parts. For this presentation, we will discuss our method to use (d,n) production reaction on deuterium in a windowless gas target system. This approach is required because of the large power of the 7 MeV, 300 μA deuteron beams. We will discuss our facility and its capabilities. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Design of high-brightness TEM00-mode solar-pumped laser for renewable material processing

    Science.gov (United States)

    Liang, D.; Almeida, J.

    2014-08-01

    The conversion of sunlight into laser light by direct solar pumping is of ever-increasing importance because broadband, temporally constant, sunlight is converted into laser light, which can be a source of narrowband, collimated, rapidly pulsed, radiation with the possibility of obtaining extremely high brightness and intensity. Nonlinear processes, such as harmonic generation, might be used to obtain broad wavelength coverage, including the ultraviolet wavelengths, where the solar flux is very weak. The direct excitation of large lasers by sunlight offers the prospect of a drastic reduction in the cost of coherent optical radiation for high average power materials processing. This renewable laser has a large potential for many applications such as high-temperature materials processing, renewable magnesium-hydrogen energy cycle and so on. We propose here a scalable TEM00 mode solar laser pumping scheme, which is composed of four firststage 1.13 m diameter Fresnel lenses with its respective folding mirrors mounted on a two-axis automatic solar tracker. Concentrated solar power at the four focal spots of these Fresnel lenses are focused individually along a common 3.5 mm diameter, 70 mm length Nd:YAG rod via four pairs of second-stage fused-silica spherical lenses and third-stage 2D-CPCs (Compound Parabolic Concentrator), sitting just above the laser rod which is also double-pass pumped by four V-shaped pumping cavities. Distilled water cools both the rod and the concentrators. 15.4 W TEM00 solar laser power is numerically calculated, corresponding to 6.7 times enhancement in laser beam brightness.

  8. Design of a plasma discharge circuit for particle wakefield acceleration

    CERN Document Server

    Anania, M P; Cianchi, A; Di Giovenale, D; Ferrario, M; Flora, F; Gallerano, G P; Ghigo, A; Marocchino, A; Massimo, F; Mostacci, A; Mezi, L; Musumeci, P; Serio, M; 10.1016/j.nima.2013.10.053

    2014-01-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV m^-1), enabling acceleration of electrons to GeV energy in few centimetres. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators; radiofrequency-based accelerators, in fact, are limited in the accelerating field (10-100 MV m^-1) requiring therefore kilometric distances to reach the GeV energies, but can provide very bright electron bunches. Combining high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of shor...

  9. Next Generation High Brightness Electron Beams From Ultra-High Field Cryogenic Radiofrequency Photocathode Sources

    CERN Document Server

    Rosenzweig, J B; Dolgashev, V; Emma, C; Fukusawa, A; Li, R; Limborg, C; Maxson, J; Musumeci, P; Nause, A; Pakter, R; Pompili, R; Roussel, R; Spataro, B; Tantawi, S

    2016-01-01

    Recent studies of the performance of radio-frequency (RF) copper structures operated at cryogenic temperatures have shown a dramatic increase in the maximum surface electric field that may be reached. We propose to utilize this development to enable a new generation of photoinjectors operated at cryogenic temperatures that may attain, through enhancement of the launch field at the photocathode by a factor of four, well over an order of magnitude increase in peak electron beam brightness. We present detailed studies of the beam dynamics associated with such a system, concentrating on an emittance-compensated S-band photoinjector that may directly substitute that of the LCLS X-ray free-electron laser. We show in this case that the increase in brightness leads directly to a factor of two reduction in gain length, with attendant increase in X-ray radiative efficiency. Extreme low emittance scenarios obtained at low operating charge, appropriate for dramatically pushing performance limits of ultrafast electron dif...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel [Stanford Univ., CA (United States)

    2011-05-01

    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.

  11. High energy gain of trapped electrons in a tapered, diffraction-dominated inverse-free-electron laser.

    Science.gov (United States)

    Musumeci, P; Tochitsky, S Ya; Boucher, S; Clayton, C E; Doyuran, A; England, R J; Joshi, C; Pellegrini, C; Ralph, J E; Rosenzweig, J B; Sung, C; Tolmachev, S; Travish, G; Varfolomeev, A A; Varfolomeev, A A; Yarovoi, T; Yoder, R B

    2005-04-22

    Energy gain of trapped electrons in excess of 20 MeV has been demonstrated in an inverse-free-electron-laser (IFEL) accelerator experiment. A 14.5 MeV electron beam is copropagated with a 400 GW CO2 laser beam in a 50 cm long undulator strongly tapered in period and field amplitude. The Rayleigh range of the laser, approximately 1.8 cm, is much shorter than the undulator length yielding a diffraction-dominated interaction. Experimental results on the dependence of the acceleration on injection energy, laser focus position, and laser power are discussed. Simulations, in good agreement with the experimental data, show that most of the energy gain occurs in the first half of the undulator at a gradient of 70 MeV/m and that the structure in the measured energy spectrum arises because of higher harmonic IFEL interaction in the second half of the undulator.

  12. Extension of the Free-Electron Laser-Amplifier Code Tda to Resonator Configurations

    NARCIS (Netherlands)

    Faatz, B.; Best, R. W. B.; Oepts, D.; van Amersfoort, P. W.; Tran, T. M.

    1993-01-01

    The investigation of many interesting, complex phenomena in a free-electron laser (FEL) requires the use of numerical computer codes. In this paper we describe the extension of one such code (TDA), which in its original form could only be used to study free-electron laser amplifiers, to include reso

  13. Extension of the Free-Electron Laser-Amplifier Code Tda to Resonator Configurations

    NARCIS (Netherlands)

    Faatz, B.; Best, R. W. B.; Oepts, D.; van Amersfoort, P. W.; Tran, T. M.

    1993-01-01

    The investigation of many interesting, complex phenomena in a free-electron laser (FEL) requires the use of numerical computer codes. In this paper we describe the extension of one such code (TDA), which in its original form could only be used to study free-electron laser amplifiers, to include

  14. Hemostatic properties of the free-electron laser

    Science.gov (United States)

    Cram, Gary P., Jr.; Copeland, Michael L.

    1998-09-01

    We have investigated the hemostatic properties of the free-electron laser (FEL) and compared these properties to the most commonly used commercial lasers in neurosurgery, CO 2 and Nd:YAG, using an acute canine model. Arterial and venous vessels, of varying diameters from 0.1 to 1.0 mm, were divided with all three lasers. Analysis of five wavelengths of the FEL (3.0, 4.5, 6.1, 6.45, and 7.7 microns) resulted in bleeding without evidence of significant coagulation, regardless of whether the vessel was an artery or vein. Hemorrhage from vessels less than 0.4 mm diameter was subsequently easily controlled with Gelfoam® (topical hemostatic agent) alone, whereas larger vessels required bipolar electrocautery. No significant charring, or contraction of the surrounding parenchyma was noted with any of the wavelengths chosen from FEL source. The CO 2 laser, in continuous mode, easily coagulated vessels with diameters of 4 mm and less, while larger vessels displayed significant bleeding requiring bipolar electrocautery for control. Tissue charring was noted with application of the CO 2 laser. In super pulse mode, the CO 2 laser exhibited similar properties, including significant charring of the surrounding parenchyma. The Nd:YAG coagulated all vessels tested up to 1.4 mm, which was the largest diameter cortical artery found, however this laser displayed significant and extensive contraction and retraction of the surrounding parenchyma. In conclusion, the FEL appears to be a poor hemostatic agent. Our results did not show any benefit of the FEL over current conventional means of achieving hemostasis. However, control of hemorrhage was easily achieved with currently used methods of hemostasis, namely Gelfoam® or bipolar electrocuatery. Although only cortical vessels in dogs were tested, we feel this data can be applied to all animals, including humans, and the peripheral, as well as central, vasculature, as our data on the CO 2 and Nd:YAG appear to closely support previous

  15. X-ray free-electron lasers principles, properties and applications f*9493

    CERN Document Server

    Stöhr, J

    2002-01-01

    Creating matter from the vacuum, taking an atomic scale motion picture of a chemical process in a time of a few femtoseconds (1 fs = 10 sup - sup 1 sup 5 sec) or unraveling the complex molecular structure of a single protein or virus. These are some of the new exciting experiments envisioned with a novel radiation source, the X-ray free-electron laser (FEL). John Madey and collaborators built the first FEL in the 1970s. It is a powerful and challenging combination of particle accelerator and laser physics and technology. Until recently FELs have been operating at infrared or near ultraviolet wavelengths. A combination of theoretical, experimental, and technological advances has made possible their extension to the X-ray region. X rays have allowed us to see the invisible for almost a century. With their help we have been making great progress in understanding the properties of materials and of living systems. Today the best sources of X rays utilize synchrotron radiation from relativistic electron beams in st...

  16. Circular dichroism measurements at an x-ray free-electron laser with polarization control

    Science.gov (United States)

    Hartmann, G.; Lindahl, A. O.; Knie, A.; Hartmann, N.; Lutman, A. A.; MacArthur, J. P.; Shevchuk, I.; Buck, J.; Galler, A.; Glownia, J. M.; Helml, W.; Huang, Z.; Kabachnik, N. M.; Kazansky, A. K.; Liu, J.; Marinelli, A.; Mazza, T.; Nuhn, H.-D.; Walter, P.; Viefhaus, J.; Meyer, M.; Moeller, S.; Coffee, R. N.; Ilchen, M.

    2016-08-01

    A non-destructive diagnostic method for the characterization of circularly polarized, ultraintense, short wavelength free-electron laser (FEL) light is presented. The recently installed Delta undulator at the LCLS (Linac Coherent Light Source) at SLAC National Accelerator Laboratory (USA) was used as showcase for this diagnostic scheme. By applying a combined two-color, multi-photon experiment with polarization control, the degree of circular polarization of the Delta undulator has been determined. Towards this goal, an oriented electronic state in the continuum was created by non-resonant ionization of the O2 1s core shell with circularly polarized FEL pulses at hν ≃ 700 eV. An also circularly polarized, highly intense UV laser pulse with hν ≃ 3.1 eV was temporally and spatially overlapped, causing the photoelectrons to redistribute into so-called sidebands that are energetically separated by the photon energy of the UV laser. By determining the circular dichroism of these redistributed electrons using angle resolving electron spectroscopy and modeling the results with the strong-field approximation, this scheme allows to unambiguously determine the absolute degree of circular polarization of any pulsed, ultraintense XUV or X-ray laser source.

  17. First demonstration of a free-electron laser driven by electrons from a laser irradiated photocathode

    Science.gov (United States)

    Curtin, Mark; Bennett, Glenn; Burke, Robert; Benson, Stephen; Madey, J. M. J.

    Results are reported from the first observation of a free-electron laser (FEL) driven by an electron beam from a laser-irradiated photocathode. The Rocketdyne/Stanford FEL achieved sustained oscillations lasting over three hours and driven by photoelectrons accelerated by the Stanford Mark III radio-frequency linac. A LaB6 cathode, irradiated by a tripled Nd:YAG mode-locked drive laser, is the source of the photoelectrons. The drive laser, operating at 95.2 MHz, is phase-locked to the 30th subharmonic of the S-band linac. Peak currents in excess of 125 amps are observed and delivered to the Rocketdyne two-meter undulator, which is operated as a stand-alone oscillator. The electron beam has an energy spread of 0.8 percent (FWHM) at 38.5 MeV and an emittance, at the undulator, comparable to that observed for thermionic operation of the electron source. Small signal gain in excess of 150 percent is observed. Preliminary estimates of the electron beam brightness deliverable to the undulator range from 3.5 to 5.0 x 10 to the 11 amps/sq m.

  18. Compact compressive arc and beam switchyard for energy recovery linac-driven ultraviolet free electron lasers

    Science.gov (United States)

    Akkermans, J. A. G.; Di Mitri, S.; Douglas, D.; Setija, I. D.

    2017-08-01

    High gain free electron lasers (FELs) driven by high repetition rate recirculating accelerators have received considerable attention in the scientific and industrial communities in recent years. Cost-performance optimization of such facilities encourages limiting machine size and complexity, and a compact machine can be realized by combining bending and bunch length compression during the last stage of recirculation, just before lasing. The impact of coherent synchrotron radiation (CSR) on electron beam quality during compression can, however, limit FEL output power. When methods to counteract CSR are implemented, appropriate beam diagnostics become critical to ensure that the target beam parameters are met before lasing, as well as to guarantee reliable, predictable performance and rapid machine setup and recovery. This article describes a beam line for bunch compression and recirculation, and beam switchyard accessing a diagnostic line for EUV lasing at 1 GeV beam energy. The footprint is modest, with 12 m compressive arc diameter and ˜20 m diagnostic line length. The design limits beam quality degradation due to CSR both in the compressor and in the switchyard. Advantages and drawbacks of two switchyard lines providing, respectively, off-line and on-line measurements are discussed. The entire design is scalable to different beam energies and charges.

  19. Compact compressive arc and beam switchyard for energy recovery linac-driven ultraviolet free electron lasers

    Directory of Open Access Journals (Sweden)

    J. A. G. Akkermans

    2017-08-01

    Full Text Available High gain free electron lasers (FELs driven by high repetition rate recirculating accelerators have received considerable attention in the scientific and industrial communities in recent years. Cost-performance optimization of such facilities encourages limiting machine size and complexity, and a compact machine can be realized by combining bending and bunch length compression during the last stage of recirculation, just before lasing. The impact of coherent synchrotron radiation (CSR on electron beam quality during compression can, however, limit FEL output power. When methods to counteract CSR are implemented, appropriate beam diagnostics become critical to ensure that the target beam parameters are met before lasing, as well as to guarantee reliable, predictable performance and rapid machine setup and recovery. This article describes a beam line for bunch compression and recirculation, and beam switchyard accessing a diagnostic line for EUV lasing at 1 GeV beam energy. The footprint is modest, with 12 m compressive arc diameter and ∼20  m diagnostic line length. The design limits beam quality degradation due to CSR both in the compressor and in the switchyard. Advantages and drawbacks of two switchyard lines providing, respectively, off-line and on-line measurements are discussed. The entire design is scalable to different beam energies and charges.

  20. Integrating a Machine Protection System for High-Current Free Electron Lasers and Energy Recovery Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Trent Allison; James Coleman; Richard Evans; Al Grippo; Kevin Jordan

    2002-09-01

    A fully integrated Machine Protection System (MPS) is critical to efficient commissioning and safe operation of all high-current accelerators. The MPS needs to monitor the status of all devices that could enter the beam path, the beam loss monitors (BLMs), magnet settings, beam dump status, etc. This information is then presented to the electron source controller, which must limit the beam power or shut down the beam completely. The MPS for the energy recovery linac (ERL) at the Jefferson Lab Free Electron Laser [1] generates eight different power limits, or beam modes, which are passed to the drive laser pulse controller (DLPC) (photocathode source controller). These range from no beam to nearly 2 megawatts of electron beam power. Automatic masking is used for the BLMs during low-power modes when one might be using beam viewers. The system also reviews the setup for the two different beamlines, the IR path or the UV path, and will allow or disallow operations based on magnet settings and valve positions. This paper will describe the approach taken for the JLab 10-kW FEL. Additional details can be found on our website http://laser.jlab.org [2].

  1. Circular dichroism measurements at an x-ray free-electron laser with polarization control

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, G.; Shevchuk, I.; Walter, P.; Viefhaus, J. [Deutsches Elektronen-Synchrotron, Notkestraße 85, 22607 Hamburg (Germany); Lindahl, A. O. [PULSE at Stanford, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Knie, A. [Institut für Physik, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany); Hartmann, N.; Lutman, A. A.; MacArthur, J. P.; Glownia, J. M.; Helml, W.; Huang, Z.; Marinelli, A.; Nuhn, H.-D.; Moeller, S.; Coffee, R. N.; Ilchen, M., E-mail: markus.ilchen@xfel.eu [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Buck, J.; Galler, A.; Liu, J. [European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); and others

    2016-08-15

    A non-destructive diagnostic method for the characterization of circularly polarized, ultraintense, short wavelength free-electron laser (FEL) light is presented. The recently installed Delta undulator at the LCLS (Linac Coherent Light Source) at SLAC National Accelerator Laboratory (USA) was used as showcase for this diagnostic scheme. By applying a combined two-color, multi-photon experiment with polarization control, the degree of circular polarization of the Delta undulator has been determined. Towards this goal, an oriented electronic state in the continuum was created by non-resonant ionization of the O{sub 2} 1s core shell with circularly polarized FEL pulses at hν ≃ 700 eV. An also circularly polarized, highly intense UV laser pulse with hν ≃ 3.1 eV was temporally and spatially overlapped, causing the photoelectrons to redistribute into so-called sidebands that are energetically separated by the photon energy of the UV laser. By determining the circular dichroism of these redistributed electrons using angle resolving electron spectroscopy and modeling the results with the strong-field approximation, this scheme allows to unambiguously determine the absolute degree of circular polarization of any pulsed, ultraintense XUV or X-ray laser source.

  2. Compact 13.5-nm free-electron laser for extreme ultraviolet lithography

    Directory of Open Access Journals (Sweden)

    Y. Socol

    2011-04-01

    Full Text Available Optical lithography has been actively used over the past decades to produce more and more dense integrated circuits. To keep with the pace of the miniaturization, light of shorter and shorter wavelength was used with time. The capabilities of the present 193-nm UV photolithography were expanded time after time, but it is now believed that further progress will require deployment of extreme ultraviolet (EUV lithography based on the use of 13.5-nm radiation. However, presently no light source exists with sufficient average power to enable high-volume manufacturing. We report here the results of a study that shows the feasibility of a free-electron laser EUV source driven by a multiturn superconducting energy-recovery linac (ERL. The proposed 40×20  m^{2} facility, using MW-scale consumption from the power grid, is estimated to provide about 5 kW of average EUV power. We elaborate the self-amplified spontaneous emission (SASE option, which is presently technically feasible. A regenerative-amplifier option is also discussed. The proposed design is based on a short-period (2–3 cm undulator. The corresponding electron beam energy is about 0.5–1.0 GeV. The proposed accelerator consists of a photoinjector, a booster, and a multiturn ERL.

  3. Characterization and control of femtosecond electron and X-ray beams at free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Christopher

    2012-11-15

    X-ray free-electron lasers (FELs) open up new frontiers in photon science, and in order to take full advantage of these unique accelerator-based light sources, the characterization and control of the femtosecond electron and X-ray beams is essential. Within this cumulative thesis, recent results achieved within the active research field of femtosecond electron and X-ray beams at FELs are reported.The basic principles of X-ray FELs are described, and concepts of longitudinal electron beam diagnostics with femtosecond accuracy are covered. Experimental results obtained with a transverse deflecting structure (TDS) and spectroscopy of coherent terahertz radiation are presented, and the suppression of coherent optical radiation effects, required for diagnostics utilizing a TDS, is demonstrated. Control of the longitudinal phase space by using multiple radio frequencies for longitudinal electron beam tailoring is presented, and a new technique of reversible electron beam heating with two TDSs is described. For the characterization of femtosecond X-ray pulses, a novel method based on dedicated longitudinal phase space diagnostics for electron beams is introduced, and recent measurements with a streaking technique using external terahertz fields are presented.

  4. High-Power Free-Electron Lasers Driven by RF Linear Accelerators

    Science.gov (United States)

    1989-05-16

    Sands Miss. Range, NM 88002-1198 University of California, Berkeley Berkeley, CA 94720 Dr. David Cartwright Los Alamos National Laboratory Prof. Frank...Prof. V. Jaccarino Dr. Darwin Ho Univ. of Calif. at Santa Barbara L-477 Santa Barbara, CA 93106 Lawrence Livermore National Laboratory P. 0. Box 808 Dr

  5. Synchrotron light sources and free-electron lasers accelerator physics, instrumentation and science applications

    CERN Document Server

    Khan, Shaukat; Schneider, Jochen; Hastings, Jerome

    2016-01-01

    Hardly any other discovery of the nineteenth century did have such an impact on science and technology as Wilhelm Conrad Röntgen’s seminal find of the X-rays. X-ray tubes soon made their way as excellent instruments for numerous applications in medicine, biology, materials science and testing, chemistry and public security. Developing new radiation sources with higher brilliance and much extended spectral range resulted in stunning developments like the electron synchrotron and electron storage ring and the freeelectron laser. This handbook highlights these developments in fifty chapters. The reader is given not only an inside view of exciting science areas but also of design concepts for the most advanced light sources. The theory of synchrotron radiation and of the freeelectron laser, design examples and the technology basis are presented. The handbook presents advanced concepts like seeding and harmonic generation, the booming field of Terahertz radiation sources and upcoming brilliant light sources dri...

  6. High brightness direct diode laser with kW output power

    Science.gov (United States)

    Fritsche, Haro; Kruschke, Bastian; Koch, Ralf; Ferrario, Fabio; Kern, Holger; Pahl, Ulrich; Pflueger, Silke; Gries, Wolfgang

    2014-03-01

    High power, high brightness diode lasers are beginning to challenge solid state lasers, i.e. disk and fiber lasers. The core technologies for brightness scaling of diode lasers are optical stacking and dense spectral combining (DSC), as well as improvements of the diode material. Diode lasers will have the lowest cost of ownership, highest efficiency and most compact design among all lasers. In our modular product design tens of single emitters are combined in a compact package and launched into a 200 μm fiber with 0.08 NA. Dense spectral combining enables power scaling from 80 W to kilowatts. Volume Bragg Gratings and dichroic filters yield high optical efficiencies of more than 80% at low cost. Each module emits up to 500 W with a beam quality of 5.5 mm*mrad and less than 20 nm linewidth. High speed switching power supplies are integrated into the module and rise times as short as 6 μs have been demonstrated. Fast control algorithms based on FPGA and embedded microcontroller ensure high wall plug efficiency with a unique control loop time of only 30 μs. Individual modules are spectrally combined to result in direct diode laser systems with kilowatts of output power at identical beam quality. For low loss fiber coupling a 200 μm fiber is used and the NA is limited to 0.08 corresponding to a beam quality of 7.5 mm*mrad. The controller architecture is fully scalable without sacrificing loop time. We leverage automated manufacturing for cost effective, high yield production. A precision robotic system handles and aligns the individual fast axis lenses and tracks all quality relevant data. Similar technologies are also deployed for dense spectral combining aligning the VBG and dichroic filters. Operating at wavelengths between 900 nm and 1100 nm, these systems are mainly used in cutting and welding, but the technology can also be adapted to other wavelength ranges, such as 793 nm and 1530 nm. Around 1.5 μm the diodes are already successfully used for resonant

  7. Phenomena Elucidation of High Brightness Fiber Laser Welding of Stainless Steel

    Science.gov (United States)

    Kawahito, Yousuke; Mizutani, Masami; Katayama, Seiji

    phenomena, 10 kW high-brightness fiber laser welding, which can produce sound welds, was confirmed to be one of the highest-quality, high-efficiency processes owing to a small effect of weakly-ionized plume and deep keyhole with a sufficient inlet for the incident laser beam absorption.

  8. Generation of a high-brightness pulsed positron beam for the Munich scanning positron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Piochacz, Christian

    2009-11-20

    Within the present work the prerequisites for the operation of the Munich scanning positron microscope (SPM) at the high intense neutron induced positron source Munich (NEPOMUC) were established. This was accomplished in two steps: Firstly, a re-moderation device was installed at the positron beam facility NEPOMUC, which enhances the brightness of the positron beam for all connected experiments. The second step was the design, set up and initial operation of the SPM interface for the high efficient conversion of the continuous beam into a bunched beam. The in-pile positron source NEPOMUC creates a positron beam with a diameter of typically 7 mm, a kinetic energy of 1 keV and an energy spread of 50 eV. The NEPOMUC re-moderator generates from this beam a low energy positron beam (20 - 200 eV) with a diameter of less than 2 mm and an energy spread well below 2.5 eV. This was achieved with an excellent total efficiency of 6.55{+-}0.25 %. The re-moderator was not only the rst step to implement the SPM at NEPOMUc, it enables also the operation of the pulsed low energy positron beam system (PLEPS). Within the present work, at this spectrometer rst positron lifetime measurements were performed, which revealed the defect types of an ion irradiated uranium molybdenum alloy. Moreover, the instruments which were already connected to the positron beam facility bene ts considerably of the high brightness enhancement. In the new SPM interface an additional re-moderation stage enhances the brightness of the beam even more and will enable positron lifetime measurements at the SPM with a lateral resolution below 1 {mu}m. The efficiency of the re-moderation process in this second stage was 24.5{+-}4.5 %. In order to convert high efficiently the continuous positron beam into a pulsed beam with a repetition rate of 50 MHz and a pulse duration of less than 50 ps, a sub-harmonic pre-bucher was combined with two sine wave bunchers. Furthermore, the additional re-moderation stage of the

  9. Beam dynamics in an initial part of a high Brightness electron linac

    CERN Document Server

    Ayzatsky, M I; Dovbnya-Kushnir, V A

    2001-01-01

    The paper is focused on problems of obtained a bright electron beam in a system that includes a grid-controlled electron gun,a klystron type type subharmonical buncher, a standing wave fundamental buncher with increasing accelerating field and a short travelling wave accelerating section. Beam focusing is provided by a longitudinal solenoidal magnetic field.It was shown that the proposed system can provide electron bunches with a peak current more than 100 A and normalized r.m.s. emittance no more than phi centre dot mm centre dot mrad.

  10. Characteristics of a high brightness gaseous field ion source employing tungsten-carbon doped NiAl needles

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Marwan S., E-mail: mmousa@mutah.edu.jo [Department of Physics, Mu' tah University, P.O. Box 7, Al-Karak (Jordan)

    2011-05-15

    We report on the characterization of a high brightness gaseous field ion source using an emitter made of a NiAl needle containing tiny spherical tungsten-carbon precipitates. By field evaporation of such a multiphase alloy, a surface protrusion is formed out of a precipitate, which can act as a small source size field ion emitter. The emission current-voltage characteristics of this emitter were recorded for a variety of parameters. The results obtained suggest that its application as a stable ion source is possible even on long term operation. -- Research highlights: {yields} High brightness gaseous field ion source of precipitation hardened NiAl+W+C emitter. {yields} Emission current-voltage characteristics are recorded for a variety of parameters. {yields} Very small virtual source sizes and energy spreads can be attained. {yields} Results suggest that application as long term stable ion source is possible.

  11. The High Luminosity Challenge: potential and limitations of High Intensity High Brightness in the LHC and its injectors

    CERN Document Server

    De Maria, R; Banfi, D; Barranco, J; Bartosik, H; Benedetto, E; Bruce, R; Brüning, O; Calaga, R; Cerutti, F; Damerau, H; Esposito, L; Fartoukh, S; Fitterer, M; Garoby, R; Gilardoni, S; Giovannozzi, M; Goddard, B; Gorini, B; Hanke, K; Iadarola, G; Lamont, M; Meddahi, M; Métral, E; Mikulec, B; Mounet, N; Papaphilippou, Y; Pieloni, T; Redaelli, S; Rossi, L; Rumolo, G; Shaposhnikova, E; Sterbini, G; Todesco, E; Tomás, R; Zimmermann, F; Valishev, A

    2014-01-01

    High-intensity and high-brightness beams are key ingredients to maximize the LHC integrated luminosity and to exploit its full potential. This contribution describes the optimization of beam and machine parameters to maximize the integrated luminosity as seen by the LHC experiments, by taking into account the expected intensity and brightness reach of LHC itself and its injector chain as well as the capabilities of the detectors for next run and foreseen upgrade scenarios.

  12. High brightness, high current injector design for the ATF upgrade at Brookhaven National Laboratory

    Science.gov (United States)

    Stratakis, Diktys

    2015-04-01

    Brookhaven National Accelerator Test Facility (BNL ATF) is in the process of moving to a new place and upgrading its major capabilities: The electron beam energy and CO2 laser power. Specifically, the maximum electron beam energy will be first projected to 100-150 MeV and then upgraded to 500 MeV while at the same time the laser power will increase 100 fold, thus making the new ATF a powerful tool in advanced accelerator concept research. The bright electron bunch produced by the new state-of-the-art photocathode rf gun will be accelerated and optionally delivered to multiple beamlines. The injector is a key element of this accelerator upgrade. It must deliver a high average current beam with very small transverse and longitudinal emittances, at a sufficiently high energy that space charge effects are under control. We review here the detailed injector design and present first results from beam dynamics simulations. We give emphasis in the production of compressed flat beams which have important applications in novel light-source concepts and could possibly alleviate the need for damping rings in lepton colliders. We present a theoretical model and with the aid of simulation examine the influence of space charge, bunch compression and suggest a operating regime with minimal phase space dilutions.

  13. Three-dimensional model of small signal free-electron lasers

    Directory of Open Access Journals (Sweden)

    Stephen Webb

    2011-05-01

    Full Text Available Coherent electron cooling is an ultrahigh-bandwidth form of stochastic cooling which utilizes the charge perturbation from Debye screening as a seed for a free-electron laser. The amplified and frequency-modulated signal that results from the free-electron laser process is then used to give an energy-dependent kick on the hadrons in a bunch. In this paper, we present a theoretical description of a high-gain free-electron laser with applications to a complete theoretical description of coherent electron cooling.

  14. Imaging Molecular Structure and Dynamics utilizing X-ray Free-Electron-Laser Sources

    OpenAIRE

    Küpper, Jochen

    2015-01-01

    Imaging controlled molecules with ultrashort x- ray pulses from free-electron lasers enables the recording of “molecular movies”, i.e., snapshots of molecules at work, with spatial (picometer) and temporal (femtosecond) atomic resolution.

  15. Proceedings of the workshop prospects for a 1 angstrom free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, J.C. (ed.)

    1990-01-01

    This report contains papers on the following topics free-electron laser theory, scaling relations and simulations; micro-wigglers; photocathode and switched power gun; applications; and summary of working groups.

  16. Design and Analysis of an Electron Gun/Booster and Free Electron Laser Optical Theory

    Science.gov (United States)

    2010-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DISSERTATION DESIGN AND ANALYSIS OF AN ELECTRON GUN/BOOSTER AND FREE ELECTRON LASER OPTICAL THEORY by...298-102 September 2010 Dissertation Design and Analysis of an Electron Gun/Booster and Free Electron Laser Optical Theory Niles, Sean P. Naval...motor attached to a spool for adjusting the bead’s position in the cavity. The bead is a small piece of stainless steel hypodermic needle threaded

  17. High-power free-electron maser operated in a two-mode frequency-multiplying regime

    Directory of Open Access Journals (Sweden)

    N. Yu. Peskov

    2016-06-01

    Full Text Available The frequency multiplication effects in high-power free-electron masers (FEM with Bragg cavities were studied to provide the advance of the oscillators into short-wavelength bands. Theoretical analysis of frequency-multiplying FEMs was carried out within the framework of the averaged coupled-wave approach. Proof-of-principle experiments were performed based on a moderately relativistic induction linac LIU-3000 (JINR. As a result, an FEM multiplier operated with a megawatt power level in the 6-mm and 4-mm wavelength bands at the second and third harmonics, respectively, was realized. The possibility of using two-mode bichromatic FEMs for powering a double-frequency accelerating structure was discussed.

  18. Design and installation of a low particulate, ultrahigh vacuum system for a high power free-electron laser

    CERN Document Server

    Dyll, Aa; Feldl, E; Parkinson, J; Preble, J; Siggins, T; Williams, S; Wisema, M

    1999-01-01

    A high-average power (kW) infrared (IR) free-electron laser (FEL) is currently being commissioned for the Jefferson Laboratory FEL User Facility. The IR FEL is driven by a unique superconducting rf linac which is recirculated to recover electron beam power that is not radiated in the FEL. The design and installation of the vacuum system for the FEL involved particular attention to minimizing particulate contamination which could cause problems with the superconducting acceleration cavities and the high power FEL optics. Particulate contamination levels of all vacuum components were monitored during the cleaning process using laser scattering. Cleaning, transport, and installation procedures were developed to minimize the contamination of the complete system. We will summarize a data base we compiled of particulate contamination levels of the various components installed in the FEL vacuum system.

  19. Present status of the infrared free-electron laser of the Institute of Scientific and Industrial Research, Osaka University

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, Shuichi; Isoyama, Goro; Honda, Yoshihide; Kato, Ryukou; Tagawa, Seiichi [Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research

    1997-03-01

    A free-electron laser with a 38-MeV L-band linear accelerator was developed at the Institute of Scientific and Industrial Research, Osaka University. The self-amplified spontaneous emission was observed at wavelengths of 20 and 40 {mu}m with a high-intensity single-bunch beam passing through a wiggler. In the oscillation experiments with a multibunch beam laser light was obtained at wavelengths from 32 to 40 {mu}m. The peak power in a micropulse of the laser is estimated to be 8.3 MW at a wavelength of 40 {mu}m. In order to apply the laser to basic researches some components of the linac and the optical cavity are being improved. (author)

  20. Using Quasi-3D OSIRIS simulations of LWFA to study generating high brightness electron beams using ionization and density downramp injection

    Science.gov (United States)

    Dalichaouch, Thamine; Davidson, Asher; Xu, Xinlu; Yu, Peicheng; Tsung, Frank; Mori, Warren; Li, Fei; Zhang, Chaojie; Lu, Wei; Vieira, Jorge; Fonseca, Ricardo

    2016-10-01

    In the past few decades, there has been much progress in theory, simulation, and experiment towards using Laser wakefield acceleration (LWFA) as the basis for designing and building compact x-ray free-electron-lasers (XFEL) as well as a next generation linear collider. Recently, ionization injection and density downramp injection have been proposed and demonstrated as a controllable injection scheme for creating higher quality and ultra-bright relativistic electron beams using LWFA. However, full-3D simulations of plasma-based accelerators are computationally intensive, sometimes taking 100 millions of core-hours on today's computers. A more efficient quasi-3D algorithm was developed and implemented into OSIRIS using a particle-in-cell description with a charge conserving current deposition scheme in r - z and a gridless Fourier expansion in ϕ. Due to the azimuthal symmetry in LWFA, quasi-3D simulations are computationally more efficient than 3D cartesian simulations since only the first few harmonics in are needed ϕ to capture the 3D physics of LWFA. Using the quasi-3D approach, we present preliminary results of ionization and down ramp triggered injection and compare the results against 3D LWFA simulations. This work was supported by DOE and NSF.

  1. NASA-DoD Lead-Free Electronics Project: Vibration Test

    Science.gov (United States)

    Woodrow, Thomas A.

    2010-01-01

    Vibration testing was conducted by Boeing Research and Technology (Seattle) for the NASA-DoD Lead-Free Electronics Solder Project. This project is a follow-on to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAA/JG-PP) Lead-Free Solder Project which was the first group to test the reliability of lead-free solder joints against the requirements of the aerospace/miLItary community. Twenty seven test vehicles were subjected to the vibration test conditions (in two batches). The random vibration Power Spectral Density (PSD) input was increased during the test every 60 minutes in an effort to fail as many components as possible within the time allotted for the test. The solder joints on the components were electrically monitored using event detectors and any solder joint failures were recorded on a Labview-based data collection system. The number of test minutes required to fail a given component attached with SnPb solder was then compared to the number of test minutes required to fail the same component attached with lead-free solder. A complete modal analysis was conducted on one test vehicle using a laser vibrometer system which measured velocities, accelerations, and displacements at one . hundred points. The laser vibrometer data was used to determine the frequencies of the major modes of the test vehicle and the shapes of the modes. In addition, laser vibrometer data collected during the vibration test was used to calculate the strains generated by the first mode (using custom software). After completion of the testing, all of the test vehicles were visually inspected and cross sections were made. Broken component leads and other unwanted failure modes were documented.

  2. First lasing of the Darmstadt cw free electron laser

    CERN Document Server

    Brunken, M; Eichhorn, R; Genz, H; Gräf, H D; Loos, H; Richter, A; Schweizer, B; Stascheck, A; Wesp, T

    1999-01-01

    The Darmstadt CW FEL designed for wavelengths between 3 and 10 mu m driven by the superconducting electron accelerator S-DALINAC first lased on December 1st, 1996 and has operated thereafter successfully in the wavelength region between 6.6 and 7.8 mu m. The pulsed electron beam employed had a micro pulse length of about 2ps, with a repetition rate of 10 MHz and a peak current of 2.7 A while its energy was varied between 29.6 and 31.5 MeV. A wedged pole hybrid undulator, with 80 periods each of 0.032 m length and a magnetic field strength of 0.15-0.4T, was located in between a 15.01 m long optical cavity equipped with two high reflectivity (99.8) mirrors of 0.05 m diameter. Due to the low beam current special care with respect to the electron and optical beam properties was necessary to meet the stringent conditions in order to reach a minute small signal gain of at least a few percent resulting in amplification. Saturation was obtained after about 2000 repetitions of the photon pulse inside the cavity. The D...

  3. Critical issues for high-brightness heavy-ion beams- prioritized

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A W; Cohen, R; Davidson, R; Faltens, A; Friedman, A; Grisham, L; Grote, D P; Haber, I; Kaganovich, I; Covo, M K; Kwan, J W; Lee, E; Logan, B G; Lund, S M; Qin, H; Seidl, P A; Sharp, W M; Vay, J L; Yu, S S

    2007-02-28

    This study group was initiated to consider whether there were any ''show-stopper'' issues with accelerators for heavy-ion warm-dense matter (WDM) and heavy-ion inertial fusion energy (HIF), and to prioritize them. Showstopper issues would appear as limits to beam current; that is, the beam would be well-behaved below the current limit, and significantly degraded in current or emittance if the current limit were exceeded at some region of an accelerator. We identified 14 issues: 1-6 could be addressed in the near term, 7-10 are potentially attractive solutions to performance and cost issues but are not yet fully characterized, 11-12 involve multibeam effects that cannot be more than partially studied in near-term facilities, and 13-14 involve new issues that are present in some novel driver concepts. Comparing the issues with the new experimental, simulation, and theoretical tools that we have developed, it is apparent that our new capabilities provide an opportunity to re-examine and significantly increase our understanding of the number one issue--halo growth and mitigation.

  4. Electro-optical characteristics of a chiral hybrid in-plane switching liquid crystal mode for high brightness.

    Science.gov (United States)

    Gwag, Jin Seog; Sohn, Kyunghwa; Kim, Young-Ki; Kim, Jae-Hoon

    2008-08-04

    We propose a new in-plane switching (IPS) nematic liquid crystal (LC) mode which uses a twist effect with a hybrid LC alignment and interdigitated electrodes as an approach for a high brightness. This is optimized to a normally white mode to minimize loss of transmittance at the electrode compared to the conventional IPS mode. The proposed mode shows an excellent dark state because the bulk LCs are aligned in parallel to the optic axis of the polarizer under low electric fields. Consequently, this proposed mode exhibits a much higher contrast ratio (980:1) than that of the conventional IPS mode (550:1).

  5. Numerical treatment of retarded radiation effects from high brightness electron beams

    Directory of Open Access Journals (Sweden)

    A. R. Rossi

    2009-10-01

    Full Text Available A form is given of the retarded electric field and magnetic induction generated by the motion of a charged particle that expresses these fields as integrals of the retarded charge density only, with kernels depending on the charge velocity and acceleration fields. In the case of a single pointlike charge, the usual Liénard-Wiechert fields follow very easily. The set of equations for the dynamics of particles in assigned electromagnetic fields with the self-consistent field is written and integrated. The code Retar for the dynamics of charged particles in external and self-consistent fields is described and a few examples of benchmark are proposed. As a physical application, the case of an electron beam moving in a bending magnetic dipole is examined, and the radiation produced analyzed, in order to characterize a therahertz radiation source.

  6. Compensating microphonics in SRF cavities to ensure beam stability for future free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Axel

    2008-07-21

    In seeded High-Gain-Harmonic-Generation free electron lasers or energy recovery linear accelerators the requirements for the bunch-to-bunch timing and energy jitter of the beam are in the femtosecond and per mill regime. This implies the ability to control the cavity radiofrequency (RF) field to an accuracy of 0.02 in phase and up to 1.10{sup -4} in amplitude. For the planned BESSY-FEL it is envisaged to operate 144 superconducting 1.3 GHz cavities of the 2.3 GeV driver linac in continuous wave mode and at a low beam current. The cavity resonance comprises a very narrow bandwidth of the order of tens of Hertz. Such cavities have been characterized under accelerator like conditions in the HoBiCaT test facility. It was possible to measure the error sources affecting the field stability in continuous wave (CW) operation. Microphonics, the main error source for a mechanical detuning of the cavities, lead to an average fluctuation of the cavity resonance of 1-5 Hz rms. Furthermore, the static and dynamic Lorentz force detuning and the helium pressure dependance of the cavity resonance have been measured. Single cavity RF control and linac bunch-to-bunch longitudinal phase space modeling containing the measured properties showed, that it is advisable to find means to minimize the microphonics detuning by mechanical tuning. Thus, several fast tuning systems have been tested for CW operation. These tuners consist of a motor driven lever for slow and coarse tuning and a piezo that is integrated into the tuner support for fast and fine tuning. Regarding the analysis of the detuning spectrum an adaptive feedforward method based on the least-mean-square filter algorithm has been developed for fast cavity tuning. A detuning compensation between a factor of two and up to a factor of seven has been achieved. Modeling the complete system including the fast tuning scheme, showed that the requirements of the BESSY-FEL are attainable. (orig.)

  7. Transverse Laser Beam Shaping in High Brightness Electron Gun at ATF

    CERN Document Server

    Roychowdhury, S

    2005-01-01

    The brightness of electron beams from a photo injector is influenced by the transverse and longitudinal distribution of the laser beam illuminating the cathode. Previous studies at Brookhaven Accelerator Test Facility have shown that formation of an ideal e-beam with lowest transverse emittance requires uniform circular distribution of the emitted electrons. The use of the uniformly distributed power of the laser beam may not lead to that of the emitted electrons because of the non-uniform quantum efficiency. A proper shaping of the laser beam can compensate for this non-uniformity. In this paper we describe the use of digital light processing (DLP) technique based on digital mirror device (DMD) for spatial modulation of the laser beam, for measurements of the quantum efficiency map, and for creating the desirable e-beam density profiles. A DMD is aμelectronic mechanical system (MEMS) comprising of millions of highly reflectiveμmirrors controlled by underlying electronics. We present exper...

  8. Unexpected High Brightness Temperature 140 PC from the Core in the Jet of 3C 120

    CERN Document Server

    Roca-Sogorb, Mar; Agudo, Ivan; Marscher, Alan P; Jorstad, Svetlana G

    2009-01-01

    We present 1.7, 5, 15, 22 and 43 GHz polarimetric multi--epoch VLBA observations of the radio galaxy 3C 120. The higher frequency observations reveal a new component, not visible before April 2007, located 80 mas from the core (which corresponds to a deprojected distance of 140 pc), with a brightness temperature about 600 times higher than expected at such distances. This component (hereafter C80) is observed to remain stationary and to undergo small changes in its brightness temperature during more than two years of observations. A combination of jet bending, significant flow acceleration, and a very strong shock --for such large distance from the core-- may explain the unusually high Tb of C80, but it seems very unlikely that this corresponds to the usual shock that emerges from the core and travels downstream to the location of C80. It appears that some other intrinsic process in the jet, capable of providing a local burst in particle and/or magnetic field energy, may be responsible for the enhanced bright...

  9. Active Detection and Imaging of Nuclear Materials with High-Brightness Gamma Rays

    Energy Technology Data Exchange (ETDEWEB)

    Barty, C J; Gibson, D J; Albert, F; Anderson, S G; Anderson, G G; Betts, S M; Berry, R D; Fisher, S E; Hagmann, C A; Johnson, M S; Messerly, M J; Phan, H H; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P

    2009-02-26

    A Compton scattering {gamma}-ray source, capable of producing photons with energies ranging from 0.1 MeV to 0.9 MeV has been commissioned and characterized, and then used to perform nuclear resonance fluorescence (NRF) experiments. The performances of the two laser systems (one for electron production, one for scattering), the electron photoinjector, and the linear accelerator are also detailed, and {gamma}-ray results are presented. The key source parameters are the size (0.01 mm{sup 2}), horizontal and vertical divergence (6 x 10 mrad{sup 2}), duration (10 ps), spectrum and intensity (10{sup 5} photons/shot). These parameters are summarized by the peak brightness, 1.5 x 10{sup 15} photons/mm{sup 2}/mrad{sup 2}/s/0.1% bandwidth, measured at 478 keV. Additional measurements of the flux as a function of the timing difference between the drive laser pulse and the relativistic photo-electron bunch, {gamma}-ray beam profile, and background evaluations are presented. These results are systematically compared to theoretical models and computer simulations. NRF measurements performed on {sup 7}Li in LiH demonstrate the potential of Compton scattering photon sources to accurately detect isotopes in situ.

  10. Terahertz-driven linear electron acceleration

    CERN Document Server

    Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2014-01-01

    The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

  11. Generation of Phase-Locked Pulses from a Seeded Free-Electron Laser.

    Science.gov (United States)

    Gauthier, David; Ribič, Primož Rebernik; De Ninno, Giovanni; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Bojanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca

    2016-01-15

    In a coherent control experiment, light pulses are used to guide the real-time evolution of a quantum system. This requires the coherence and the control of the pulses' electric-field carrier waves. In this work, we use frequency-domain interferometry to demonstrate the mutual coherence of time-delayed pulses generated by an extreme ultraviolet seeded free-electron laser. Furthermore, we use the driving seed laser to lock and precisely control the relative phase between the two free-electron laser pulses. This new capability opens the way to a multitude of coherent control experiments, which will take advantage of the high intensity, short wavelength, and short duration of the pulses generated by seeded free-electron lasers.

  12. Propagation of gamma rays and production of free electrons in air

    CERN Document Server

    Dimant, Y S; Sprangle, P; Penano, J; Romero-Talamas, C A; Granatstein, V L

    2012-01-01

    A new concept of remote detection of concealed radioactive materials has been recently proposed \\cite{Gr.Nusin.2010}-\\cite{NusinSprangle}. It is based on the breakdown in air at the focal point of a high-power beam of electromagnetic waves produced by a THz gyrotron. To initiate the avalanche breakdown, seed free electrons should be present in this focal region during the electromagnetic pulse. This paper is devoted to the analysis of production of free electrons by gamma rays leaking from radioactive materials. Within a hundred meters from the radiation source, the fluctuating free electrons appear with the rate that may exceed significantly the natural background ionization rate. During the gyrotron pulse of about 10 microsecond length, such electrons may seed the electric breakdown and create sufficiently dense plasma at the focal region to be detected as an unambiguous effect of the concealed radioactive material.

  13. X-ray Free-Electron Lasers - Present and Future Capabilities [Invited

    Energy Technology Data Exchange (ETDEWEB)

    Galayda, John; Ratner, John Arthur:a Daniel F.; White, William E.; /SLAC

    2011-11-16

    The Linac Coherent Light Source is now in operation as an X-ray free-electron laser (FEL) user facility. It produces coherent pulses of 550-10,000 eV X-rays of duration adjustable from <10 fsto500 fs. Typical peak power is in excess of 20 GW. The facility will soon be joined by several X-ray FELs under construction around the world. This article will provide an abridged history of free-electron lasers, a description of some basic physics regarding free-electron laser light amplification, and an overview of the rapidly growing list of examples in which lasers will be used in the control and operation of X-ray FELs.

  14. X-ray free-electron lasers--present and future capabilities [Invited

    Energy Technology Data Exchange (ETDEWEB)

    Galayda, John N.; Arthur, John; Ratner, Daniel F.; White, William E. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

    2010-11-15

    The Linac Coherent Light Source is now in operation as an X-ray free-electron laser (FEL) user facility. It produces coherent pulses of 550-10,000 eV X-rays of duration adjustable from <10 fs to 500 fs. Typical peak power is in excess of 20 GW. The facility will soon be joined by several X-ray FELs under construction around the world. This article will provide an abridged history of free-electron lasers, a description of some basic physics regarding free-electron laser light amplification, and an overview of the rapidly growing list of examples in which lasers will be used in the control and operation of X-ray FELs.

  15. Free electron degeneracy effects on collisional excitation, ionization, de-excitation and three-body recombination

    Science.gov (United States)

    Tallents, G. J.

    2016-09-01

    Collisional-radiative models enable average ionization and ionization populations, plus the rates of absorption and emission of radiation to be calculated for plasmas not in thermal equilbrium. At high densities and low temperatures, electrons may have a high occupancy of the free electron quantum states and evaluations of rate coefficients need to take into account the free electron degeneracy. We demonstrate that electron degeneracy can reduce collisional rate coefficients by orders-of-magnitude from values calculated neglecting degeneracy. We show that assumptions regarding the collisional differential cross-section can alter collisional ionization and recombination rate coefficients by a further factor two under conditions relevant to inertial fusion.

  16. Hierarchic electrodynamics and free electron lasers concepts, calculations, and practical applications

    CERN Document Server

    Kulish, Victor V

    2011-01-01

    Hierarchic Electrodynamics and Free Electron Lasers: Concepts, Calculations, and Practical Applications presents intriguing new fundamental concepts in the phenomenon of hierarchical electrodynamics as a new direction in physics. Concentrating on the key theory of hierarchic oscillations and waves, this book focuses on the numerous applications of nonlinear theory in different types of high-current Free Electron Lasers (FEL), including their primary function in the calculation methods used to analyze various multi-resonant, multi-frequency nonlinear FEL models. This is considered the first boo

  17. Two-colour generation in a chirped seeded Free-Electron Laser

    CERN Document Server

    Mahieu, B; Castronovo, D; Danailov, M B; Demidovich, A; De Ninno, G; Di Mitri, S; Fawley, W M; Ferrari, E; Fröhlich, L; Gauthier, D; Giannessi, L; Mahne, N; Penco, G; Raimondi, L; Spampinati, S; Spezzani, C; Svetina, C; Trovò, M; Zangrando, M

    2013-01-01

    We present the experimental demonstration of a method for generating two spectrally and temporally separated pulses by an externally seeded, single-pass free-electron laser operating in the extreme-ultraviolet spectral range. Our results, collected on the FERMI@Elettra facility and confirmed by numerical simulations, demonstrate the possibility of controlling both the spectral and temporal features of the generated pulses. A free-electron laser operated in this mode becomes a suitable light source for jitter-free, two-colour pump-probe experiments.

  18. Two-colour generation in a chirped seeded free-electron laser: a close look.

    Science.gov (United States)

    Mahieu, Benoît; Allaria, Enrico; Castronovo, Davide; Danailov, Miltcho B; Demidovich, Alexander; De Ninno, Giovanni; Di Mitri, Simone; Fawley, William M; Ferrari, Eugenio; Fröhlich, Lars; Gauthier, David; Giannessi, Luca; Mahne, Nicola; Penco, Giuseppe; Raimondi, Lorenzo; Spampinati, Simone; Spezzani, Carlo; Svetina, Cristian; Trovò, Mauro; Zangrando, Marco

    2013-09-23

    We present the experimental demonstration of a method for generating two spectrally and temporally separated pulses by an externally seeded, single-pass free-electron laser operating in the extreme-ultraviolet spectral range. Our results, collected on the FERMI@Elettra facility and confirmed by numerical simulations, demonstrate the possibility of controlling both the spectral and temporal features of the generated pulses. A free-electron laser operated in this mode becomes a suitable light source for jitter-free, two-colour pump-probe experiments.

  19. Model for nonlinear behavior in the self-amplified spontaneous-emission free-electron laser

    Science.gov (United States)

    Krinsky, S.

    2004-06-01

    We introduce a simplified model for the saturation of a self-amplified spontaneous-emission free-electron laser. Within this model, we determine the effect of nonlinearity upon the statistical properties of the output radiation. Comparing our results with the computer simulations of Saldin, Schneidmiller, and Yurkov [The Physics of Free Electron Lasers (Springer-Verlag, Berlin, 2000)], we find that the model provides a good description of the average intensity, field correlation function, and coherence time, but underestimates the intensity fluctuation. Asymmetric spectral broadening phenomena are not included in the model.

  20. Broadband tunability of a far-infrared free-electron laser

    Science.gov (United States)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amerstoort, P. W.

    1993-08-01

    Results obtained in operation of the long-wavelength free electron laser (FEL) of the FELIX facility are presented. These involve measurements of the spectral range covered (16-110 microns), the output power, and the influence of the cavity desynchronism. The free electron laser for infrared experiments (FELIX) uses an undulator with tunable field strength that enables a factor of 2 tunability of the radiation wavelength. Results show that the dependence of the small signal gain and output power on cavity length tuning and undulator strength can be estimated. The results are compared with numerical simulations.

  1. Fast Polarization Switching Demonstration Using Crossed-Planar Undulator in a Seeded Free Electron Laser

    CERN Document Server

    Deng, Haixiao; Feng, Lie; Feng, Chao; Chen, Jianhui; Liu, Bo; Wang, Xingtao; Lan, Taihe; Wang, Guanglei; Zhang, Wenyan; Liu, Xiaoqing; Zhang, Meng; Lin, Guoqiang; Zhang, Miao; Wang, Dong; Zhao, Zhentang

    2013-01-01

    Fast polarization switching of light sources is required over a wide spectral range to investigate the symmetry of matter. In this Letter, we report the first experimental demonstration of the crossed-planar undulator technique at a seeded free-electron laser, which holds great promise for the full control and fast switching of the polarization of short-wavelength radiation. In the experiment, the polarization state of the coherent radiation at the 2nd harmonic of the seed laser is switched successfully. The experiment results confirm the theory, and pave the way for applying the crossed-planar undulator technique for the seeded X-ray free electron lasers.

  2. Mode characterization, autocorrelation measurements, and harmonic conversion with pico- and femtosecond pulses delivered by the Mark III free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Cutolo, A.; Hooper, B.; Benson, S.V.; Schultz, J.F.; Madeys, J.M.

    1989-01-01

    After briefly reporting on the present status of the infrared free-electron laser now operating at the Stanford Photon Research Laboratory and powered by the linear accelerator Mark III, we discuss the results of using nonlinear optical techniques for both the characterization of its output radiation and the enhancment of its tunability range. In particular, to show the evidence of possible self-guiding effects, a new and reliable technique has been devised and successfully tested for real-time monitoring of the micropulse evolution during the buildup of radiation. Finally, we discuss the main problems connected with the damage threshold of optical materials.

  3. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  4. Quantifying height of ultraprecisely machined steps on oxygen-free electronic copper disc using Fourier-domain short coherence interferometry

    CERN Document Server

    Montonen, Risto; Hæggström, Edward; Österberg, Kenneth

    2016-01-01

    The internal shape and alignment of accelerator discs is crucial for efficient collider operation at the future compact linear collider (CLIC). We applied a calibrated custom-made Fourier-domain short coherence interferometer to measure the height of 40 and 60μm60  μm ultraprecisely turned steps (surface roughness Ra≤25nmRa≤25  nm, flatness ≤2μm≤2  μm) on an oxygen-free electronic copper disc. The step heights were quantified to be (39.6±2.6)μm(39.6±2.6)  μm and (59.0±2.3)μm(59.0±2.3)  μm. The uncertainties are quoted at 95% confidence level and include contributions from calibration, refractive index of air, cosine error, surface roughness, and thermal expansion in comparison to standard temperature of 20°C. The results were verified by measuring the same steps using a commercial white light interferometer Veeco—NT3300. Our instrument can ensure that the accelerator discs of the CLIC are aligned within the tolerance required for efficient collider operation.

  5. Design of the extraction arc for the 2{sup nd} beam line of the free-electron laser FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Matthias

    2014-01-15

    In this thesis, I deal with the design of the extraction arc for the second beam line of FLASH, an FEL (Free-Electron Laser) user facility at DESY Hamburg. Both beam lines will use the same linear accelerator and their separation will take place behind the last accelerating module. I present the constraints for the extraction arc given by the beam line layout of the existing machine, by the building environment of the new beam line and in particular, by coherent synchrotron radiation (CSR). The impact from CSR is presented, and I show how to mitigate these effects and what that means for the beam line design. The optimization of the extraction arc was done applying the downhill simplex algorithm which is presented, first in its basic form to explain the operation principle and then in a more advanced version as used in the applied program. I introduce in this thesis the final layout of the extraction arc including the following matching section. This layout fulfills all given constraints and can provide the required electron beam quality for FEL operation. In order to prove this, I present start-to-end simulations for different bunch charges and for two different wavelengths.

  6. Quantifying height of ultraprecisely machined steps on oxygen-free electronic copper disc using Fourier-domain short coherence interferometry

    Science.gov (United States)

    Montonen, Risto; Kassamakov, Ivan; Hæggström, Edward; Österberg, Kenneth

    2016-01-01

    The internal shape and alignment of accelerator discs is crucial for efficient collider operation at the future compact linear collider (CLIC). We applied a calibrated custom-made Fourier-domain short coherence interferometer to measure the height of 40 and 60 μm ultraprecisely turned steps (surface roughness Ra≤25 nm, flatness ≤2 μm) on an oxygen-free electronic copper disc. The step heights were quantified to be (39.6±2.6) μm and (59.0±2.3) μm. The uncertainties are quoted at 95% confidence level and include contributions from calibration, refractive index of air, cosine error, surface roughness, and thermal expansion in comparison to standard temperature of 20°C. The results were verified by measuring the same steps using a commercial white light interferometer Veeco-NT3300. Our instrument can ensure that the accelerator discs of the CLIC are aligned within the tolerance required for efficient collider operation.

  7. High brightness imaging system using vertical cavity surface-emitting laser micro-arrays- results and proposed enhancements

    Science.gov (United States)

    Mentzer, Mark A.; Ghosh, Chuni L.

    2011-05-01

    Laser illumination systems for high brightness imaging through the self-luminosity of explosive events, at Aberdeen Proving Ground and elsewhere, required complex pulse timing, extensive cooling, large-scale laser systems (frequencydoubled flash-pumped Nd:YAG, Cu-vapor, Q-switched ruby), making them difficult to implement for range test illumination in high speed videography. A Vertical Cavity Surface-Emitting Laser (VCSEL) array was designed and implemented with spectral filtering to effectively remove self-luminosity and the fireball from the image, providing excellent background discrimination in a variety of range test scenarios. Further improvements to the system are proposed for applications such as imaging through murky water or dust clouds with optimal penetration of obscurants.

  8. Conceptual design of a high-brightness linac for soft X-ray SASE-FEL source

    Energy Technology Data Exchange (ETDEWEB)

    Alesini, D.; Bertolucci, S.; Biagini, M.E.; Biscari, C.; Boni, R.; Boscolo, M.; Castellano, M.; Clozza, A.; Pirro, G.D.G. Di; Drago, A.; Esposito, A.; Ferrario, M. E-mail: massimo.ferrario@lnf.infn.it; Fusco, V.; Gallo, A.; Ghigo, A.; Guiducci, S.; Incurvati, M.; Laurelli, P.; Ligi, C.; Marcellini, F.; Migliorati, M.; Milardi, C.; Palumbo, L.; Pellegrino, L.; Preger, M.; Raimondi, P.; Ricci, R.; Sanelli, C.; Sgamma, F.; Spataro, B.; Serio, M.; Stecchi, A.; Stella, A.; Tazzioli, F.; Vaccarezza, C.; Vescovi, M.; Vicario, C.; Zobov, M.; Acerbi, E.; Alessandria, F.; Barni, D.; Bellomo, G.; Birattari, C.; Bonardi, M.; Boscolo, I.; Bosotti, A.; Broggi, F.; Cialdi, S.; DeMartinis, C.; Giove, D.; Maroli, C.; Michelato, P.; Monaco, L.; Pagani, C.; Petrillo, V.; Pierini, P.; Serafini, L.; Sertore, D.; Volpini, G.; Chiadroni, E.; Felici, G.; Levi, D.; Mastrucci, M.; Mattioli, M.; Medici, G.; Petrarca, G.S.; Catani, L.; Cianchi, A.; D' Angelo, A.; Salvo, R.D.R. Di; Fantini, A.; Moricciani, D.; Schaerf, C.; Bartolini, R.; Ciocci, F.; Dattoli, G.; Doria, A.; Flora, F.; Gallerano, G.P.; Giannessi, L.; Giovenale, E.; Messina, G.; Mezi, L.; Ottaviani, P.L.; Picardi, L.; Quattromini, M.; Renieri, A.; Ronsivalle, C.; Avaldi, L.; Carbone, C.; Cricenti, A.; Pifferi, A.; Perfetti, P.; Prosperi, T.; Albertini, V.R.V. Rossi; Quaresima, C.; Zema, N

    2003-07-11

    FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R and D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNR-ENEA-INFN-University of Roma 'Tor Vergata' study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, leading to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an S-band normal conducting linac with high-brightness photoinjector integrated in an RF compressor.

  9. Non-uniform DFB-surface-etched gratings for enhanced performance high power, high brightness broad area lasers

    Science.gov (United States)

    Decker, J.; Fricke, J.; Maaßdorf, A.; Erbert, G.; Tränkle, G.; Crump, P.

    2017-02-01

    Monolithic spectral stabilization is demonstrated in narrow-stripe broad-area lasers (NBA) with high power (5W), conversion efficiency (50%) and high brightness, by using optimized high-order surface-etched DFB gratings. However, surface etched gratings introduce a high index contrast into the semiconductor, leading to the scattering losses increasing rapidly with groove etch depth, limiting efficiency and yield. We therefore review progress in the exploitation of novel, non-uniform grating configurations for improved performance. Devices with non-uniform gratings whose groove etch depth decreases toward the front facet (apodized grating) are shown to operate with enhanced spectrally stable power (6W) compared to devices with uniform gratings.

  10. Nonlinear Dynamics of High-Brightness Electron Beams and Beam-Plasma Interactions: Theories, Simulations, and Experiments

    Energy Technology Data Exchange (ETDEWEB)

    C. L. Bohn (deceased), P. Piot and B. Erdelyi

    2008-05-31

    According to its original Statement of Work (SOW), the overarching objective of this project is: 'To enhance substantially the understanding of the fundamental dynamics of nonequilibrium high-brightness beams with space charge.' Our work and results over the past three and half years have been both intense and fruitful. Inasmuch as this project is inextricably linked to a larger, growing research program - that of the Beam Physics and Astrophysics Group (BPAG) - the progress that it has made possible cannot easily be separated from the global picture. Thus, this summary report includes major sections on 'global' developments and on those that can be regarded as specific to this project.

  11. High brightness laser-diode device emitting 500 W from a 200 μm/NA0.22 fiber

    Science.gov (United States)

    Junhong, Yu; Linhui, Guo; Hualing, Wu; Zhao, Wang; Hao, Tan; Songxin, Gao; Deyong, Wu; Kai, Zhang

    2016-06-01

    A practical method of achieving high brightness and high power fiber-coupled laser-diode device is demonstrated both by experiment and ZEMAX software simulation, which is obtained by technologies of precision beam collimation, free space beam combining and polarization beam combining based on mini-bar diode laser chip. Using this method, fiber-coupled laser-diode module output power from the multimode fiber with 200 μm core diameter and 0.22 numerical aperture (NA) could reach 528 W, equalizing brightness is 11.0 MW/(cm2 sr) and electro-optical efficiency (defined as fiber output power divided by voltage and current of the module) is 43.0%. By this method, much wider applications of fiber-coupled laser-diode are anticipated.

  12. High-power high-brightness solar laser approach for renewable Mg recovery from MgO

    Science.gov (United States)

    Almeida, Joana; Liang, Dawei

    2014-08-01

    Hydrogen and heat energy from the reaction of magnesium with water can be used for engines and fuel cells. However, at least 4000 K is necessary for magnesium oxide reduction. Ultra high brightness solar-pumped lasers become essential to make this renewable process technology efficient and economically competitive. 2.3 mg/kJ solar laser - induced magnesium production efficiency has been achieved by T. Yabe et al., in 2012, by focusing a 53 W solar laser beam on a mixture of MgO with Si as reducing agent. This result is however far from the 12.1 mg/kJ attained with 2 kW/mm2 CO2 laser beam. To improve substantially the solar laser - induced Mg production efficiency, a simple high-power, high brightness Nd:YAG solar laser pumping approach is proposed. The solar radiation is both collected and concentrated by four Fresnel lenses, and redirected towards a Nd:YAG laser head by four plane folding mirrors. A fused-silica secondary concentrator is used to compress the highly concentrated solar radiation to a laser rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAXand LASCADnumerical analysis. High-record solar laser beam brightness figure of merit - defined as the ratio between laser power and the product of Mx 2 and My 2 - of 10.5 W is numerically achieved, being 5.5 times higher than the previous record and about 1600 times more than that of the most powerful Nd:YAG solar laser. 8340 W/mm2 is numerically achieved at its focal region, which can quadruple the magnesium production efficiency with clean energy.

  13. Nonlinear effects in propagation of radiation of X-ray free-electron lasers

    Science.gov (United States)

    Nosik, V. L.

    2016-05-01

    Nonlinear effects accompanying the propagation of high-intensity beams of X-ray free-electron lasers are considered. It is shown that the X-ray wave field in the crystal significantly changes due to the formation of "hollow" atomic shells as a result of the photoelectric effect.

  14. Fireworks in noble gas clusters a first experiment with the new "free-electron laser"

    CERN Multimedia

    2002-01-01

    An international group of scientists has published first experiments carried out using the new soft X-ray free-electron laser (FEL) at the research center DESY in Hamburg, Germany. Using small clusters of noble gas atoms, for the first time, researchers studied the interaction of matter with intense X-ray radiation from an FEL on extremely short time scales (1 page).

  15. First mm-wave generation in the FOM free electron maser

    NARCIS (Netherlands)

    Verhoeven, A. G. A.; Bongers, W. A.; Bratman, V. L.; Caplan, M.; Denisov, G. G.; van der Geer, C. A. J.; Manintveld, P.; Poelman, A. J.; Plomp, J.; Savilov, A. V.; Smeets, P. H. M.; Sterk, A. B.; Urbanus, W. H.

    1999-01-01

    A free electron maser (FEM) has been built as a pilot mm-wave source for applications on future fusion research devices such as international tokamak experimental reactor (ITER), A unique feature of the Dutch FEM is the possibility to tune the frequency over the entire range from 130 to 260 GHz at a

  16. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron Laser

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Bressler, Christian; Chen, Lin X.

    2013-01-01

    X-ray free electron lasers (XFELs) deliver short (<100 fs) and intense (similar to 10(12) photons) pulses of hard X-rays, making them excellent sources for time-resolved studies. Here we show that, despite the inherent instabilities of current (SASE based) XFELs, they can be used for measuring hi...

  17. Time-resolved electron spectrum diagnostics for a free-electron laser

    NARCIS (Netherlands)

    Gillespie, W. A.; MacLeod, A. M.; Martin, P. F.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1996-01-01

    Time-resolved electron-beam diagnostics have been developed for use with free-electron lasers (FELs) and associated electron sources, based on the techniques of secondary electron emission and optical transition radiation (OTR). The 32-channel OTR detector forms part of a high-resolution (0.18%) ele

  18. Status and research objectives of the Dutch free electron laser for infrared experiments

    Science.gov (United States)

    Van Amersfoort, P. W.; Best, R. W. B.; Van Buuren, R.; Delmee, P. F. M.; Faatz, B.; Van Der Geer, C. A. J.; Jaroszynski, D. A.; Manintveld, P.; Mastop, W. J.; Meddens, B. J. H.; Van Der Meer, A. F. G.; Oepts, D.; Pluygers, J.; Van Der Wiel, M. J.

    1990-10-01

    We review the status and research objectives of the free electron laser for infrared experiments (FELIX), which will be operated as a users facility for the far-infrared and submillimeter spectral regions. The spectral region between 8 and 80 μm will be covered in the first stage of the project.

  19. Broad-Band Tunability of a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amersfoort, P. W.

    1993-01-01

    A unique property of the free-electron laser (FEL) is its capability to be tuned continuously over a wide spectral range. This is a major difference with all other high-power lasers. However, the tunability of first-generation FELs used to be quite poor (typically 10% or less), due to constraints im

  20. Short-Wavelength Free-Electron Lasers with Periodic Plasma Structures

    NARCIS (Netherlands)

    Bazylev, V. A.; Schep, T. J.; Tulupov, A. V.

    1994-01-01

    Concepts of compact free-electron lasers that are based on beam-plasma interactions and that operate in the vacuum ultraviolet and x-ray wavelength ranges are discussed. Coherent radiation can not only be produced by periodic transverse motions of an electron beam, but also by its longitudinal motio

  1. Status of the high power free electron laser using the race-track microtron-recuperator

    Science.gov (United States)

    Vinokurov, N. A.; Gavrilov, N. G.; Gorniker, E. I.; Kulipanov, G. N.; Kuptsov, I. V.; Kurkin, G. Ya.; Erg, G. I.; Levashov, Yu. I.; Oreshkov, A. D.; Petrov, S. P.; Petrov, V. M.; Pinayev, I. V.; Popik, V. M.; Sedlyarov, I. K.; Shaftan, T. V.; Skrinsky, A. N.; Sokolov, A. S.; Veshcherevich, V. G.; Vobly, P. D.

    1996-02-01

    The high power infrared free electron laser is under construction at the Novosibirsk Scientific Centre. The goal of this project is to provide a user facility for Siberian Centre of Photochemical Researches. The features of the installation and its status are described.

  2. Low-loss electron beam transport in a high-power, electrostatic free-electron maser

    NARCIS (Netherlands)

    Valentini, M.; van der Geer, C. A. J.; Verhoeven, A. G. A.; van der Wiel, M. J.; Urbanus, W. H.

    1997-01-01

    At the FOM Institute for Plasma Physics ''Rijnhuizen'', The Netherlands, the commissioning of a high-power, electrostatic free-electron maser is in progress. The design target is the generation of 1 MW microwave power in the frequency range 130-260 GHz. The foreseen application o

  3. Coherent spontaneous emission and spontaneous phase locking in a free-electron laser

    NARCIS (Netherlands)

    Weits, H. H.; Oepts, D.

    1999-01-01

    We present measurements that demonstrate the existence of spontaneous coherence between independently generated laser pulses in the FELIX free-electron laser, The experiments show that the interpulse coherence is caused by a high level of coherently enhanced spontaneous emission. We have been able t

  4. Microwave Undulators and Electron Generators for New-Generation Free-Electron Lasers

    Science.gov (United States)

    Abubakirov, E. B.; Bandurkin, I. V.; Vikharev, A. A.; Kuzikov, S. V.; Rozental, R. M.; Savilov, A. V.; Fedotov, A. E.

    2016-03-01

    We discuss possible applications of relativistic pulsed microwave electronic devices in physics and engineering of modern free-electron lasers. In particular, the possibilities of using high-power millimeter-wave radiation pulses for electron pitching in the operating space of the laser (in a microwave undulator), as well as for cooling and focusing of electron bunches, are considered.

  5. Multi-dimensional free-electron laser simulation codes: a comparison study

    CERN Document Server

    Biedron, S G; Dejus, Roger J; Faatz, B; Freund, H P; Milton, S V; Nuhn, H D; Reiche, S

    2000-01-01

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

  6. Spectral Dynamics of a Free-Electron Maser with a Step-Tapered Undulator

    NARCIS (Netherlands)

    Eecen, P. J.; Schep, T. J.; Tulupov, A. V.

    1995-01-01

    The spectral behavior of a high-power, high-gain free-electron maser (FEM) is investigated. The maser has a step-tapered undulator consisting of two sections with different strengths and lengths and equal periodicities. The sections are separated by a field-free gap. The configuration is enclosed

  7. Broad-Band Tunability of a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amersfoort, P. W.

    1993-01-01

    A unique property of the free-electron laser (FEL) is its capability to be tuned continuously over a wide spectral range. This is a major difference with all other high-power lasers. However, the tunability of first-generation FELs used to be quite poor (typically 10% or less), due to constraints

  8. Three-dimensional, time-dependent simulation of a regenerative amplifier free-electron laser

    NARCIS (Netherlands)

    Freund, H.P.; Nguyen, D.C.; Sprangle, P.; Slot, van der P.J.M.

    2013-01-01

    Free-electron lasers have been designed to operate over virtually the entire electromagnetic spectrum from microwaves through x rays and in a variety of configurations including amplifiers and oscillators. Oscillators typically operate in the low-gain regime where the full spectral width is ð !=!Þ

  9. First mm-wave generation in the FOM free electron maser

    NARCIS (Netherlands)

    Verhoeven, A. G. A.; Bongers, W. A.; Bratman, V. L.; Caplan, M.; Denisov, G. G.; van der Geer, C. A. J.; Manintveld, P.; Poelman, A. J.; Plomp, J.; Savilov, A. V.; Smeets, P. H. M.; Sterk, A. B.; Urbanus, W. H.

    1999-01-01

    A free electron maser (FEM) has been built as a pilot mm-wave source for applications on future fusion research devices such as international tokamak experimental reactor (ITER), A unique feature of the Dutch FEM is the possibility to tune the frequency over the entire range from 130 to 260 GHz at

  10. High brightness microwave lamp

    Science.gov (United States)

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  11. ORAL ISSUE OF THE JOURNAL "USPEKHI FIZICHESKIKH NAUK": Ginzburg's invention of undulators and their role in modern synchrotron radiation sources and free electron lasers

    Science.gov (United States)

    Kulipanov, Gennadii N.

    2007-04-01

    Undulators — periodic magnetic structures that were originally introduced by Vitalii Ginzburg in 1947 for electromagnetic radiation generation using relativistic electrons — are among the key elements of modern synchrotron radiation sources and free electron lasers (FELs). In this talk, the history of three generations of storage ring-based synchrotron X-ray sources using wigglers and undulators is briefly traced. Prospects for two types of next-generation space-coherent X-ray sources are discussed, which use long undulators and energy recovery accelerators or, alternatively, employ linear accelerator-based FELs. The recently developed Novosibirsk terahertz FEL facility, currently the world' s most powerful terahertz source, is described. It was the generation of electromagnetic radiation in this range that Ginzburg discussed in his 1947 work.

  12. Micro-structure Engineering of InGaN/GaN Quantum Wells for High Brightness Light Emitting Devices

    KAUST Repository

    Shen, Chao

    2013-05-01

    With experimental realization of micro-structures, the feasibility of achieving high brightness, low efficiency droop blue LED was implemented based on InGaN/GaN micro-LED-pillar design. A significantly high current density of 492 A/cm2 in a 20 μm diameter (D) micro-LED-pillar was achieved, compared to that of a 200 μm diameter LED (20 A/cm2), both at 10 V bias voltage. In addition, an increase in sustained quantum efficiency from 70.2% to 83.7% at high injection current density (200 A/cm2) was observed in micro-LED-pillars in conjunction with size reduction from 80 μm to 20 μm. A correlation between the strain relief and the electrical performance improvement was established for micro-LED-pillars with D < 50 μm, apart from current spreading effect. The degree of strain relief and its distribution were further studied in micro-LED-pillars with D ranging from 1 μm to 15 μm. Significant wavenumbers down-shifts for E2 and A1 Raman peaks, together with the blue shifted PL peak emission, were observed in as-prepared pillars, reflecting the degree of strain relief. A sharp transition from strained to relaxed epitaxy region was discernible from the competing E2 phonon peaks at 572 cm-1 and 568 cm-1, which were attributed to strain residue and strain relief, respectively. A uniform strain relief at the center of micro-pillars was achieved, i.e. merging of the competing phonon peaks, after Rapid Thermal Annealing (RTA) at 950℃ for 20 seconds, 4 phenomenon of which was observed for the first time. The transition from maximum strain relief to a uniform strain relief was found along the narrow circumference (< 2.5 μm) of the pillars from the line-map of Raman spectroscopy. The extent of strain relief is also examined considering the height (L) of micro-LED-pillars fabricated using FIB micro-machining technique. The significant strain relief of up to 70% (from -1.4 GPa to -0.37 GPa), with a 71 meV PL peak blue shift, suggested that micro-LED-pillar with D < 3 μm and

  13. New Free Electron Wire for Loss Free Utilization of Electrical Energy and Highly Energy Efficient Electrical Appliances

    Directory of Open Access Journals (Sweden)

    Sabyasachi Haldar

    2014-07-01

    Full Text Available New Free Electrons Wire will enable the use of electrical energy and also energy in various other forms, in a loss free way, at room temperature. Free Electrons confined in vacuum at the order of 10-4 torr or more, at the core of the wire, can move a distance as long as about, to a few kilometers without any collision. The vacuum is maintained in a tube made up of alternate layers of Teflon and Silicon Oxynitride. The columbic repulsion between these free electrons will actually conduct energy without any loss. The free electrons trapped in vacuum tube, should be at a particular density of around 2.02 x 108 electrons per unit area. A metal encapsulation(s over the wire is there to keep the electromagnetic field remain confined within the free electron wire, to make it harmless to the health of living creatures. Apart from loss free energy transportation, the free electron wire is also capable of generating very high electromagnetic field due to the free electrons, simply by removing the metal encapsulation(s, which can be used for various purposes. The materials and techniques adopted will make New Free Electron Wire producible commercially, at the cost of general copper wires.

  14. Technology of magnetically driven accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-03-26

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab.

  15. Few-femtosecond time-resolved measurements of X-ray free-electron lasers.

    Science.gov (United States)

    Behrens, C; Decker, F-J; Ding, Y; Dolgashev, V A; Frisch, J; Huang, Z; Krejcik, P; Loos, H; Lutman, A; Maxwell, T J; Turner, J; Wang, J; Wang, M-H; Welch, J; Wu, J

    2014-04-30

    X-ray free-electron lasers, with pulse durations ranging from a few to several hundred femtoseconds, are uniquely suited for studying atomic, molecular, chemical and biological systems. Characterizing the temporal profiles of these femtosecond X-ray pulses that vary from shot to shot is not only challenging but also important for data interpretation. Here we report the time-resolved measurements of X-ray free-electron lasers by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source. We demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron and X-ray temporal characterization. A resolution of less than 1 fs root mean square has been achieved for soft X-ray pulses. The lasing evolution along the undulator has been studied with the electron trapping being observed as the X-ray peak power approaches 100 GW.

  16. Mode-selective phonon excitation in gallium nitride using mid-infrared free-electron laser

    Science.gov (United States)

    Kagaya, Muneyuki; Yoshida, Kyohei; Zen, Heishun; Hachiya, Kan; Sagawa, Takashi; Ohgaki, Hideaki

    2017-02-01

    The single-phonon mode was selectively excited in a solid-state sample. A mid-infrared free-electron laser, which was tuned to the target phonon mode, was irradiated onto a crystal cooled to a cryogenic temperature, where modes other than the intended excitation were suppressed. An A 1(LO) vibrational mode excitation on GaN(0001) face was demonstrated. Anti-Stokes Raman scattering was used to observe the excited vibrational mode, and the appearance and disappearance of the scattering band at the target wavenumber were confirmed to correspond to on and off switching of the pump free-electron laser and were fixed to the sample vibrational mode. The sum-frequency generation signals of the pump and probe lasers overlapped the Raman signals and followed the wavenumber shift of the pump laser.

  17. Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

    2012-07-01

    The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

  18. Optimization of a seeding option for the VUV free electron laser at DESY

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2000-01-01

    In order to get fully coherent radiation from the Free Electron Laser (FEL) amplifier starting from the shot noise, it is foreseen to implement a seeding option into the VUV FEL being under construction at DESY (DESY print TESLA-FEL 95-03, Hamburg, DESY, 1995, Seeding option for the VUV free electron laser at DESY: joint DESY and GKSS proposal; Available at DESY upon request only). It consists of an additional undulator, a bypass for electrons and an X-ray monochromator. This paper presents the results of optimization of the seeding option for the VUV FEL providing maximal spectral brightness at minimal shot-to-shot intensity fluctuations. Calculations are performed with three-dimensional, time-dependent simulation code FAST (Nucl. Instr. and Meth. A 429 (1999) 233).

  19. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers.

    Science.gov (United States)

    Hilbert, Vinzenz; Blinne, Alexander; Fuchs, Silvio; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Paulus, Gerhard G; Förster, Eckhart; Zastrau, Ulf

    2013-09-01

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  20. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hilbert, Vinzenz; Fuchs, Silvio; Paulus, Gerhard G.; Zastrau, Ulf [Institute of Optics and Quantum Electronics, Friedrich-Schiller University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Blinne, Alexander [Institute for Theoretical Physics, Friedrich-Schiller University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Feigl, Torsten [Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Straße 7, 07745 Jena (Germany); Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Förster, Eckhart [Institute of Optics and Quantum Electronics, Friedrich-Schiller University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz Institute, Fröbelstieg 3, 07743 Jena (Germany)

    2013-09-15

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  1. Bremsstrahlung and Line Spectroscopy of Warm Dense Aluminum Plasma Generated by EUV Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Zastrau, U; Fortmann, C; Faustlin, R; Bornath, T; Cao, L F; Doppner, T; Dusterer, S; Forster, E; Glenzer, S H; Gregori, G; Holl, A; Laarmann, T; Lee, H; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Tiggesbaumker, J; Thiele, R; Truong, N X; Uschmann, I; Toleikis, S; Tschentscher, T; Wierling, A

    2008-03-07

    We report on the novel creation of a solid density aluminum plasma using free electron laser radiation at 13.5 nm wavelength. Ultrashort pulses of 30 fs duration and 47 {micro}J pulse energy were focused on a spot of 25 {micro}m diameter, yielding an intensity of 3 x 10{sup 14} W/cm{sup 2} on the bulk Al-target. The radiation emitted from the plasma was measured using a high resolution, high throughput EUV spectrometer. The analysis of both bremsstrahlung and line spectra results in an estimated electron temperature of (30 {+-} 10) eV, which is in very good agreement with radiation hydrodynamics simulations of the laser-target-interaction. This demonstrates the feasibility of exciting plasmas at warm dense matter conditions using EUV free electron lasers and their accurate characterization by EUV spectroscopy.

  2. Compositional change in hu-man enamel irradiated with MIR free electron laser

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The purpose of this study was to investigate compositional changes in human enamel irradiated with the free electron laser (FEL). The exposure on dental enamel at the wavelength of 9.64 ?m was observed with the Beijing free electron laser. The distribution of elements in the irradiated or non-irradiated enamel was measured by scanning electron microscope (SEM) with energy-dispersive spectroscopy and synchrotron radiation X-ray fluorescence (SRXRF) in Beijing Synchrotron Radiation Facility (BSRF). The results showed that the P/Ca ratio in the ablation region of enamel at the maximum wavelength of infrared absorption was obviously smaller than that at the non-maximum wavelength. In the ablation region the ratios of P/Ca and Ca/Sr were smaller than those in the non-ablation region. The distributions of P, Ca and Sr in the ablation region were heterogeneous due to the element change caused by FEL irradiation.

  3. Effects of free-electron-laser field fluctuations on the frequency response of driven atomic resonances

    CERN Document Server

    Nikolopoulos, G M

    2012-01-01

    We study the effects of field fluctuations on the total yields of Auger electrons, obtained in the excitation of neutral atoms to a core-excited state by means of short-wavelength free-electron-laser pulses. Beginning with a self-contained analysis of the statistical properties of fluctuating free-electron-laser pulses, we analyse separately and in detail the cases of single and double Auger resonances, focusing on fundamental phenomena such as power broadening and ac Stark (Autler-Townes) splitting. In certain cases, field fluctuations are shown to influence dramatically the frequency response of the resonances, whereas in other cases the signal obtained may convey information about the bandwidth of the radiation as well as the dipole moment between Auger states.

  4. Undulator commissioning by characterization of radiation in x-ray free electron lasers

    Directory of Open Access Journals (Sweden)

    Takashi Tanaka

    2012-11-01

    Full Text Available In x-ray free electron lasers (XFELs where a long undulator composed of many segments is installed, there exist a number of error sources to reduce the FEL gain such as the trajectory error, K value discrepancy, and phase mismatch, which are related to the segmented-undulator structure. Undulator commissioning, which refers to the tuning and alignment processes to eliminate the possible error sources, is thus an important step toward realization of lasing. In the SPring-8 angstrom compact free electron laser (SACLA facility, the undulator commissioning has been carried out by means of characterization of x-ray radiation, i.e., measurements of the spatial and spectral profiles of monochromatized spontaneous undulator radiation as well as by probing the FEL intensity. The achieved tuning and alignment accuracies estimated from the statistics of actual measurements in SACLA show the effectiveness of this commissioning scheme.

  5. Effects of Laser Pulse Heating of Copper Photocathodes on High-brightness Electron Beam Production at Blowout Regime

    CERN Document Server

    Zheng, Lianmin; Tang, Chuanxiang; Gai, Wei

    2016-01-01

    Producing high-brightness and high-charge (>100 pC) electron bunches at blowout regime requires ultrashort laser pulse with high fluence. The effects of laser pulse heating of the copper photocathode are analyzed in this paper. The electron and lattice temperature is calculated using an improved two-temperature model, and an extended Dowell-Schmerge model is employed to calculate the thermal emittance and quantum efficiency. A time-dependent growth of the thermal emittance and the quantum efficiency is observed. For a fixed amount of charge, the projected thermal emittance increases with the decreasing laser radius, and this effect should be taken into account in the laser optimization at blowout regime. Moreover, laser damage threshold fluence is simulated, showing that the maximum local fluence should be less than 40 mJ/cm^2 to prevent damage to the cathode. The cryogenic effect on the laser pulse heating is studied, showing that the hazards caused by the laser pulse heating will be significantly mitigated ...

  6. High brightness, quantum-defect-limited conversion efficiency in cladding-pumped Raman fiber amplifiers and oscillators.

    Science.gov (United States)

    Heebner, John E; Sridharan, Arun K; Dawson, Jay W; Messerly, Michael J; Pax, Paul H; Shverdin, Miro Y; Beach, Raymond J; Barty, Chris P J

    2010-07-05

    We present a detailed theoretical investigation of cladding-pumped Raman fiber amplification in an unexplored parameter space of high conversion efficiency (> 60%) and high brightness enhancement (> 1000). Fibers with large clad-to-core diameter ratios can provide a promising means for Raman-based brightness enhancement of diode pump sources. Unfortunately, the diameter ratio cannot be extended indefinitely since the intensity generated in the core can greatly exceed that in the cladding long before the pump is fully depleted. If left uncontrolled, this leads to the generation of parasitic second-order Stokes wavelengths in the core, limiting the conversion efficiency and as we will show, clamping the achievable brightness enhancement. Using a coupled-wave formalism, we present the upper limit on brightness enhancement as a function of diameter ratio for conventionally guided fibers. We further present strategies for overcoming this limit based upon depressed well core designs. We consider two configurations: 1) pulsed cladding-pumped Raman fiber amplifier (CPRFA) and 2) cw cladding-pumped Raman fiber laser (CPRFL).

  7. Researching the 915 nm high-power and high-brightness semiconductor laser single chip coupling module

    Science.gov (United States)

    Wang, Xin; Wang, Cuiluan; Wu, Xia; Zhu, Lingni; Jing, Hongqi; Ma, Xiaoyu; Liu, Suping

    2017-02-01

    Based on the high-speed development of the fiber laser in recent years, the development of researching 915 nm semiconductor laser as main pumping sources of the fiber laser is at a high speed. Because the beam quality of the laser diode is very poor, the 915 nm laser diode is generally based on optical fiber coupling module to output the laser. Using the beam-shaping and fiber-coupling technology to improve the quality of output beam light, we present a kind of high-power and high-brightness semiconductor laser module, which can output 13.22 W through the optical fiber. Based on 915 nm GaAs semiconductor laser diode which has output power of 13.91 W, we describe a thoroughly detailed procedure for reshaping the beam output from the semiconductor laser diode and coupling the beam into the optical fiber of which the core diameter is 105 μm and the numerical aperture is 0.18. We get 13.22 W from the output fiber of the module at 14.5 A, the coupling efficiency of the whole module is 95.03% and the brightness is 1.5 MW/cm2 -str. The output power of the single chip semiconductor laser module achieves the advanced level in the domestic use.

  8. Heat dissipation performance of a high-brightness LED package assembly using high-thermal conductivity filler.

    Science.gov (United States)

    Yung, K C; Liem, H; Choy, H S

    2013-12-10

    This paper presents a thermal analysis and experimental validation of natural convective heat transfer of a high-brightness light-emitting diode (LED) package assembly. The substrate materials used in the LED package assembly were filled and doped using boron nitride (BN) filler. The thermal conductivity of the BN-filled substrate was measured. The temperature distribution and heat flow of the LED package were assessed by thermal profile measurement using an infrared (IR) camera and thermocouples. In addition, the heat transfer process of the LED package assembly in natural convection was also simulated using the computational fluid dynamics method. The optical performance of the LED package was monitored and investigated with various filler contents. The heat conduction mechanism in the substrate was analyzed. IR thermogram showed that the BN-doped substrate could effectively lower the surface temperature of the LED package by 21.5°C compared with the traditional FR4 substrate. According to the IESNA LM 80 lifetime testing method, reduction in LED temperature can prolong the LED's lifetime by 19,000 h. The optical performance of the LED package assembly was also found to be improved significantly in lighting power by 10%. As a result, the overall heat dissipation capability of the LED package to the surrounding is enhanced, which improves the LED's efficacy.

  9. Development, characterization and experimental performance of x-ray optics for the LCLS free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Soufli, R; Pivovaroff, M J; Baker, S L; Robinson, J C; Gullikson, E M; Mc Carville, T J; Stefan, P M; Aquila, A L; Ayers, J; McKernan, M A; Bionta, R M

    2008-09-10

    This manuscript discusses the development of reflective optics for the x-ray offset mirror systems of the Linac Coherent Light Source (LCLS), a 0.15-1.5 nm free-electron laser (FEL) at the Stanford Linear Accelerator Center (SLAC). The unique properties (such as the high peak brightness) of the LCLS FEL beam translate to strict limits in terms of materials choice, thus leading to an x-ray mirror design consisting of a reflective coating deposited on a silicon substrate. Furthermore, the physics requirements for these mirrors result in stringent surface figure and finish specifications that challenge the state-of-the-art in x-ray substrate manufacturing, thin film deposition, and metrology capabilities. Recent experimental results on the development, optimization, and characterization of the LCLS soft x-ray mirrors are presented in this manuscript, including: precision surface metrology on the silicon substrates, and the development of boron carbide reflective coatings with reduced stress and thickness variation < 0.14 nm rms across the 175-mm clear aperture area of the LCLS soft x-ray mirrors.

  10. Free-electron masers vs. gyrotrons: prospects for high-power sources at millimeter and submillimeter wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Thumm, Manfred E-mail: manfred.thumm@ihm.fzk.de

    2002-05-01

    The possible applications of high-power millimeter (mm) and sub-mm waves from free-electron masers (FEMs) and gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power mm waves generated by long pulse or continuous wave (CW) gyrotron oscillators and short pulse very high-power FEMs in the areas of RF-plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as electron cyclotron resonance heating (28-170 GHz), electron cyclotron current drive , collective Thomson scattering , microwave transmission and heat-wave propagation experiments. Continuously frequency tunable FEMs could widen these fields of applications. Another important application of CW gyrotrons is industrial materials processing, e.g. sintering of high-performance functional and structural nanostructured ceramics. Sub-mm wave sources are employed in high-frequency broadband electron paramagnetic resonance and other types of spectroscopy. Future applications which await the development of novel high-power FEM amplifiers and gyro-amplifiers include high-resolution radar ranging and imaging in atmospheric and planetary science as well as deep-space and specialized satellite communications and RF drivers for next-generation high-gradient linear accelerators (supercolliders). The present paper reviews the state-of-the-art and future prospects of these recent applications of gyro-devices and FEMs and compares their specific advantages.

  11. Equation of state of the relativistic free electron gas at arbitrary degeneracy

    Science.gov (United States)

    Faussurier, Gérald

    2016-12-01

    We study the problem of the relativistic free electron gas at arbitrary degeneracy. The specific heat at constant volume and particle number CV and the specific heat at constant pressure and particle number CP are calculated. The question of equation of state is also studied. Non degenerate and degenerate limits are considered. We generalize the formulas obtained in the non-relativistic and ultra-relativistic regimes.

  12. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

    NARCIS (Netherlands)

    Nelson, A. J.; Toleikis, S.; Chapman, H.; Bajt, S.; Krzywinski, J.; Chalupsky, J.; Juha, L.; Cihelka, J.; Hajkova, V.; Vysin, L.; Burian, T.; Kozlova, M.; Faustlin, R. R.; Nagler, B.; Vinko, S. M.; Whitcher, T.; Dzelzainis, T.; Renner, O.; Saksl, K.; Khorsand, A. R.; Heimann, P. A.; Sobierajski, R.; Klinger, D.; Jurek, M.; Pelka, J.; Iwan, B.; Andreasson, J.; Timneanu, N.; Fajardo, M.; Wark, J. S.; Riley, D.; Tschentscher, T.; Hajdu, J.; Lee, R. W.

    2009-01-01

    We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OA

  13. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

    NARCIS (Netherlands)

    Nelson, A. J.; Toleikis, S.; Chapman, H.; Bajt, S.; Krzywinski, J.; Chalupsky, J.; Juha, L.; Cihelka, J.; Hajkova, V.; Vysin, L.; Burian, T.; Kozlova, M.; Faustlin, R. R.; Nagler, B.; Vinko, S. M.; Whitcher, T.; Dzelzainis, T.; Renner, O.; Saksl, K.; Khorsand, A. R.; Heimann, P. A.; Sobierajski, R.; Klinger, D.; Jurek, M.; Pelka, J.; Iwan, B.; Andreasson, J.; Timneanu, N.; Fajardo, M.; Wark, J. S.; Riley, D.; Tschentscher, T.; Hajdu, J.; Lee, R. W.

    2009-01-01

    We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OA

  14. Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

    NARCIS (Netherlands)

    Nelson, A. J.; Toleikis, S.; Chapman, H.; Bajt, S.; Krzywinski, J.; Chalupsky, J.; Juha, L.; Cihelka, J.; Hajkova, V.; Vysin, L.; Burian, T.; Kozlova, M.; Faustlin, R. R.; Nagler, B.; Vinko, S. M.; Whitcher, T.; Dzelzainis, T.; Renner, O.; Saksl, K.; Khorsand, A. R.; Heimann, P. A.; Sobierajski, R.; Klinger, D.; Jurek, M.; Pelka, J.; Iwan, B.; Andreasson, J.; Timneanu, N.; Fajardo, M.; Wark, J. S.; Riley, D.; Tschentscher, T.; Hajdu, J.; Lee, R. W.

    2009-01-01

    We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The

  15. Optical Transition Radiation Measurement of Electron Beam for Beijing Free Electron Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiang; XIE Jia-Lin; LI Yong-Gui; ZHUANG Jie-Jia

    2001-01-01

    We used transition radiation techniques instead of the original phosphor targets to improve the electronic beam diagnostic system at Beijing Free Electron Laser. The beam profile, size (3.3 × 2.4 mm), position and divergence angle (σrms = 2.5 mrad) in transverse have been obtained from optical transition radiation. We also present the experimental set-up and some preliminary results.

  16. Free Electron Laser For The Siberian Centre For Photochemical Research The Control System

    CERN Document Server

    Avlasov, Y K; Miginskaya, E G; Oreshkov, A D; Ovchar, A V; Salikova, T V; Selivanov, P A; Serednyakov, S I; Tararyshkin, S V; Tribendis, A G; Vinokurov, N A

    2004-01-01

    This article describes the software for the control system of the Free Electron Laser for the Siberian Center for photochemical research. The main components of subsystems composing the control system as well as their hardware and software components are considered. Also main features of each of the subsystems and of the whole control system are mentioned. The prospects of control system development to meet the future requirements are discussed.

  17. Status of polarization control experiment at Shanghai deep ultraviolet free electron laser

    CERN Document Server

    Deng, Haixiao; Feng, Lie; Liu, Bo; Chen, Jianhui; Dai, Zhimin; Fan, Yong; Feng, Chao; He, Yongzhou; Lan, Taihe; Song, Lin; Wang, Dong; Wang, Xingtao; Wang, Zhishan; Zhang, Jidong; Zhang, Meng; Zhang, Miao; Zhao, Zhentang

    2012-01-01

    A polarization control experiment by utilizing a pair of crossed undulators has been proposed for the Shanghai deep ultraviolet free electron laser test facility. Numerical simulations indicate that, with the electromagnetic phase-shifter located between the two crossed planar undulators, fully coherent radiation with 100 nJ order pulse energy, 5 picoseconds pulse length and circular polarization degree above 90% could be generated. The physical design study and the preparation status of the experiment are presented in the paper.

  18. Electron trajectories in free electron laser with realizable helical wiggler and ion channel guiding

    Directory of Open Access Journals (Sweden)

    S. Ebrahimi

    2004-12-01

    Full Text Available   A detailed analysis of electron trajectories in a realizable helical wiggler free electron laser with ion channel guiding using electron (single particle dynamics is presented. Conditions for stability of electron orbit have been investigated, calculations are made to illustrate. Conclusion shows that there are differences stable (unstable condition(s electron trajectories between ideal helical wiggler(2D and realizable helical wiggler (3D.

  19. 3-D numerical analysis of a high-gain free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, J.C.

    1988-10-19

    We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab.

  20. Identification of the Amplification Mechanism in the First Free-Electron Laser as Net Stimulated Free-Electron Two-Quantum Stark Emission

    Institute of Scientific and Technical Information of China (English)

    S.H.Kim

    2009-01-01

    We find that the electron phase with respect to the incident laser radiation must be random in the first freeelectron laser (FEL) and, hence, the incident laser radiation works as a relaxation force to keep a Maxwellian distribution. We formulate the threshold laser intensity for amplification which agrees with the measured value in the order of magnitude in the first FEL. The magnetic wiggler must produce an electric wiggler whose period is the same as that of the magnetic wiggler. We find that net stimulated free-electron two-quantum Stark (FETQS)emission driven by this electric wiggler is the mechanism responsible t'or the measured ga/n and the measured laser intensity at the plateau in the first FEL.

  1. Direct and secondary nuclear excitation with x-ray free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Gunst, Jonas; Wu, Yuanbin, E-mail: yuanbin.wu@mpi-hd.mpg.de; Kumar, Naveen; Keitel, Christoph H.; Pálffy, Adriana, E-mail: Palffy@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2015-11-15

    The direct and secondary nuclear excitation produced by an x-ray free electron laser when interacting with a solid-state nuclear target is investigated theoretically. When driven at the resonance energy, the x-ray free electron laser can produce direct photoexcitation. However, the dominant process in that interaction is the photoelectric effect producing a cold and very dense plasma in which also secondary processes such as nuclear excitation by electron capture may occur. We develop a realistic theoretical model to quantify the temporal dynamics of the plasma and the magnitude of the secondary excitation therein. Numerical results show that depending on the nuclear transition energy and the temperature and charge states reached in the plasma, secondary nuclear excitation by electron capture may dominate the direct photoexcitation by several orders of magnitude, as it is the case for the 4.8 keV transition from the isomeric state of {sup 93}Mo, or it can be negligible, as it is the case for the 14.4 keV Mössbauer transition in {sup 57}Fe. These findings are most relevant for future nuclear quantum optics experiments at x-ray free electron laser facilities.

  2. Chirped pulse amplification in an extreme-ultraviolet free-electron laser

    Science.gov (United States)

    Gauthier, David; Allaria, Enrico; Coreno, Marcello; Cudin, Ivan; Dacasa, Hugo; Danailov, Miltcho Boyanov; Demidovich, Alexander; di Mitri, Simone; Diviacco, Bruno; Ferrari, Eugenio; Finetti, Paola; Frassetto, Fabio; Garzella, David; Künzel, Swen; Leroux, Vincent; Mahieu, Benoît; Mahne, Nicola; Meyer, Michael; Mazza, Tommaso; Miotti, Paolo; Penco, Giuseppe; Raimondi, Lorenzo; Ribič, Primož Rebernik; Richter, Robert; Roussel, Eléonore; Schulz, Sebastian; Sturari, Luca; Svetina, Cristian; Trovò, Mauro; Walker, Paul Andreas; Zangrando, Marco; Callegari, Carlo; Fajardo, Marta; Poletto, Luca; Zeitoun, Philippe; Giannessi, Luca; de Ninno, Giovanni

    2016-12-01

    Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3-4.4 nm).

  3. Chirped pulse amplification in an extreme-ultraviolet free-electron laser.

    Science.gov (United States)

    Gauthier, David; Allaria, Enrico; Coreno, Marcello; Cudin, Ivan; Dacasa, Hugo; Danailov, Miltcho Boyanov; Demidovich, Alexander; Di Mitri, Simone; Diviacco, Bruno; Ferrari, Eugenio; Finetti, Paola; Frassetto, Fabio; Garzella, David; Künzel, Swen; Leroux, Vincent; Mahieu, Benoît; Mahne, Nicola; Meyer, Michael; Mazza, Tommaso; Miotti, Paolo; Penco, Giuseppe; Raimondi, Lorenzo; Ribič, Primož Rebernik; Richter, Robert; Roussel, Eléonore; Schulz, Sebastian; Sturari, Luca; Svetina, Cristian; Trovò, Mauro; Walker, Paul Andreas; Zangrando, Marco; Callegari, Carlo; Fajardo, Marta; Poletto, Luca; Zeitoun, Philippe; Giannessi, Luca; De Ninno, Giovanni

    2016-12-01

    Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3-4.4 nm).

  4. EM Structure Based and Vacuum Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Colby, E.R.; /SLAC

    2005-09-27

    The importance of particle acceleration may be judged from the number of applications which require some sort of accelerated beam. In addition to accelerator-based high energy physics research, non-academic applications include medical imaging and treatment, structural biology by x-ray diffraction, pulse radiography, cargo inspection, material processing, food and medical instrument sterilization, and so on. Many of these applications are already well served by existing technologies and will profit only marginally from developments in accelerator technology. Other applications are poorly served, such as structural biology, which is conducted at synchrotron radiation facilities, and medical treatment using proton accelerators, the machines for which are rare because they are complex and costly. Developments in very compact, high brightness and high gradient accelerators will change how accelerators are used for such applications, and potentially enable new ones. Physical and technical issues governing structure-based and vacuum acceleration of charged particles are reviewed, with emphasis on practical aspects.

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

    CERN Document Server

    Feng, Chao; Deng, Haixiao; Zhao, Zhentang

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Chao Feng

    2014-07-01

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

  7. The nature of free electrons in superfluid helium - a test of quantum mechanics and a basis to review its foundations and make a comparison to classical theory

    Energy Technology Data Exchange (ETDEWEB)

    Mills, R.L. [BlackLight Power, Inc., Cranbury, NJ (United States)

    2001-10-01

    The Schroedinger equation was originally postulated in 1926 as having a solution of the one electron atom. It gives the principal energy levels of the hydrogen atom as eigenvalues of eigenfunction solutions of the Laguerre differential equation. But, as the principal quantum number n>>1, the eigenfunctions become nonsensical. Despite its wide acceptance, on deeper inspection, the Schroedinger solution is plagued with many failings as well as difficulties in terms of a physical interpretation that have caused it to remain controversial since its inception. Only the one electron atom may be solved without approximations, but it fails to predict electron spin and leads to models with nonsensical consequences such as negative energy states of the vacuum, infinities, and negative kinetic energy. In addition to many predictions which simply do not agree with observations, the Schroedinger equation predicts noncausality, nonlocality, spooky actions at a distance or quantum telepathy, perpetual motion, and many internal inconsistencies where contradicting statements have to be taken true simultaneously. Recently, the behavior of free electrons in superfluid helium has again forced the issue of the meaning of the wave function. Electrons form bubbles in superfluid helium which reveal that the electron is real and that a physical interpretation of the wave function is necessary. Furthermore, when irradiated with light of energy of about a 0.5 to several electron volts (H.J. Marris, J. Low Temp. Phys. 120 (2000) 173), the electrons carry current at different rates as if they exist with different sizes. It has been proposed that the behavior of free electrons in superfluid helium can be explained in terms of the electron breaking into pieces at superfluid helium temperatures (H.J. Marris, J. Low Temp. Phys. 120 (2000) 173). Yet, the electron has proven to be indivisible even under particle accelerator collisions at 90 GeV (LEPII). The nature of the wave function must now be

  8. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2007-01-01

    Particle Accelerator Physics is an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. Part I gathers the basic tools, recalling the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part II is an extensive primer in beam dynamics, followed in Part III by the introduction and description of the main beam parameters. Part IV is devoted to the treatment of perturbations in beam dynamics. Part V discusses the details of charged particle accleration. Part VI and Part VII introduce the more advanced topics of coupled beam dynamics and the description of very intense beams. Part VIII is an exhaustive treatment of radiation from accelerated charges and introduces important sources of coherent radiation such as synchrotrons and free-electron lasers. Part IX collects the appendices gathering useful mathematical and physical formulae, parameters and units. Solutions to many end-of-chapter problems are give...

  9. Synchronization of Chaotic Storage-Ring Free-Electron Laser by Bi-Directional Coupling Scheme with the Coupling Strength Varied Periodically

    Institute of Scientific and Technical Information of China (English)

    HUANG Liang-Yu; LUO Xiao-Shu

    2006-01-01

    @@ We analyse the chaotic dynamics of storage-ring free-electron lasers and report a bi-directional coupled scheme with the coupling strength varied periodically to synchronize two chaotic storage-ring free-electron lasers.

  10. Quantum confinement in perovskite oxide heterostructures: Tight binding instead of a nearly free electron picture

    OpenAIRE

    Zhong, Zhicheng; Zhang, Qinfang; Held, Karsten

    2013-01-01

    Most recently, orbital-selective quantum well states of $d$ electrons have been experimentally observed in SrVO$_3$ ultrathin films [K. Yoshimatsu et. al., Science 333, 319 (2011)] and SrTiO$_3$ surfaces [A. F. Santander-Syro et. al., Nature 469, 189 (2011)]. Hitherto, one tries to explain these experiments by a nearly free electron (NFE) model, an approach widely used for delocalized electrons in semiconductor heterostructures and simple metal films. We show that a tight binding (TB) model i...

  11. Proposals for gain cascading in single-pass of a free-electron laser oscillator

    CERN Document Server

    Deng, Haixiao

    2016-01-01

    The low-gain free electron laser (FEL) oscillators are cutting-edge tools to produce fully coherent radiation in the spectral region from terahertz to vacuum ultraviolet, and potentially in hard X-ray. In this paper, it is proposed to utilize an oscillator with multi-stage undulators to enable gain cascading in a single pass of FEL oscillator, making it possible to achieve shorter pulses and higher power than classical FEL oscillators. Theoretical analysis and numerical simulations in the infrared and hard X-ray regions show that our proposal is effective and practically simple to implement.

  12. Ultrashort electromagnetic clusters formation by two-stream superheterodyne free electron lasers

    DEFF Research Database (Denmark)

    Kulish, Viktor V.; Lysenko, Alexander V.; Volk, Iurii I.

    2016-01-01

    A cubic nonlinear self-consistent theory of multiharmonic two-stream superheterodyne free electron lasers (TSFEL) of a klystron type, intended to form powerful ultrashort clusters of an electromagnetic field is constructed. Plural three-wave parametric resonant interactions of wave harmonics have...... been taken into account. An amplitude, phase and spectral analyses of the processes occurring in such devices have been carried out. The conditions necessary for the forming of the ultrashort clusters of an electromagnetic field have been found out. The possibility of the ultrashort electromagnetic...

  13. A free-electron laser for cyclotron resonant heating in magnetic fusion reactors

    Science.gov (United States)

    Freund, H. P.; Read, M. E.; Jackson, R. H.; Pershing, D. E.; Taccetti, J. M.

    1995-05-01

    A G-band free-electron laser designed for plasma heating is described using a coaxial hybrid iron (CHI) wiggler formed by insertion into a solenoid of a central rod and an outer ring of alternating ferrite and nonferrite spacers positioned so that the central ferrite (nonferrite) spacers are opposite the outer nonferrite (ferrite) spacers. The CHI wiggler provides for enhanced beam focusing and the ability to handle intense beams and high-power continuous wave radiation. Simulations indicate that a power/efficiency of 3.5 MW/13% are possible using a 690 kV/40 A beam. No beam loss was found in simulation.

  14. Coherent-pulse 2D crystallography using a free-electron laser x-ray source.

    Science.gov (United States)

    Mancuso, A P; Schropp, A; Reime, B; Stadler, L-M; Singer, A; Gulden, J; Streit-Nierobisch, S; Gutt, C; Grübel, G; Feldhaus, J; Staier, F; Barth, R; Rosenhahn, A; Grunze, M; Nisius, T; Wilhein, T; Stickler, D; Stillrich, H; Frömter, R; Oepen, H-P; Martins, M; Pfau, B; Günther, C M; Könnecke, R; Eisebitt, S; Faatz, B; Guerassimova, N; Honkavaara, K; Kocharyan, V; Treusch, R; Saldin, E; Schreiber, S; Schneidmiller, E A; Yurkov, M V; Weckert, E; Vartanyants, I A

    2009-01-23

    Coherent diffractive imaging for the reconstruction of a two-dimensional (2D) finite crystal structure with a single pulse train of free-electron laser radiation at 7.97 nm wavelength is demonstrated. This measurement shows an advance on traditional coherent imaging techniques by applying it to a periodic structure. It is also significant that this approach paves the way for the imaging of the class of specimens which readily form 2D, but not three-dimensional crystals. We show that the structure is reconstructed to the detected resolution, given an adequate signal-to-noise ratio.

  15. Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

    Directory of Open Access Journals (Sweden)

    E. Principi

    2016-03-01

    Full Text Available High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium state of matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excess of 10 eV and a cold solid-density ion lattice. The obtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangement of the sample electronic structure around the Fermi level occurring on a time scale of about 100 fs.

  16. Electron Beam Spectrum Diagnostics with Optical Transition Radiation on the Beijing Free-Electron Laser

    Institute of Scientific and Technical Information of China (English)

    李泉凤; 吴频; 高建江; 吴刚

    2004-01-01

    A measurement system was developed to measure the electron beam spectrum of the Beijing free-electron laser based on the optical transition radiation (OTR). This paper describes the system, which consists of a 32-channel high resolution of 0.02% OTR detector, especially the spectrometer. The OTR angular-distribution pattern at the focal plane has two apexes, but the two apexes are smoothed out due to the electron beam energy distribution. The energy spectrum can be measured if the magnet energy resolution is higher than 0.7% to distinguish the electron beam energy distribution.

  17. Beam shaping to improve the free-electron laser performance at the Linac Coherent Light Source

    Science.gov (United States)

    Ding, Y.; Bane, K. L. F.; Colocho, W.; Decker, F.-J.; Emma, P.; Frisch, J.; Guetg, M. W.; Huang, Z.; Iverson, R.; Krzywinski, J.; Loos, H.; Lutman, A.; Maxwell, T. J.; Nuhn, H.-D.; Ratner, D.; Turner, J.; Welch, J.; Zhou, F.

    2016-10-01

    A new operating mode has been developed for the Linac Coherent Light Source (LCLS) in which we shape the longitudinal phase space of the electron beam. This mode of operation is realized using a horizontal collimator located in the middle of the first bunch compressor to truncate the head and tail of the beam. With this method, the electron beam longitudinal phase space and current profile are reshaped, and improvement in lasing performance can be realized. We present experimental studies at the LCLS of the beam shaping effects on the free-electron laser performance.

  18. Pair Production from Vacuum at the Focus of an X-Ray Free Electron Laser

    OpenAIRE

    Ringwald, A.

    2001-01-01

    There are definite plans for the construction of X-ray free electron lasers (FEL), both at DESY, where the so-called XFEL is part of the design of the electron-positron linear collider TESLA, as well as at SLAC, where the so-called Linac Coherent Light Source (LCLS) has been proposed. Such an X-ray laser would allow for high-field science applications: One could make use of not only the high energy and transverse coherence of the X-ray beam, but also of the possibility of focusing it to a spo...

  19. Growth rate enhancement of free-electron laser by two consecutive wigglers with axial magnetic field

    Indian Academy of Sciences (India)

    A Hasanbeigi; A Farhadian; E Khademi Bidhendi

    2014-06-01

    The operative mechanism for a free-electron laser (FEL) with two consecutive helical wigglers having opposite circular polarization in the presence of an axial magnetic field is proposed and analysed. With the help of fluid theory, a tenth-degree polynomial dispersion equation for electromagnetic and space-charge waves is derived. The results are used to illustrate and discuss the dependence of growth rate on different system parameters. Finally, it is shown that for the same system parameters the growth rate of the proposed structure is more than the growth rate of instability in a conventional FEL.

  20. Toward atomic resolution diffractive imaging of isolated molecules with x-ray free-electron lasers

    CERN Document Server

    Stern, Stephan; Filsinger, Frank; Rouzée, Arnaud; Rudenko, Artem; Johnsson, Per; Martin, Andrew V; Barty, Anton; Bostedt, Christoph; Bozek, John D; Coffee, Ryan N; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Hartmann, Robert; Kimmel, Nils; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Rudek, Benedikt; Starodub, Dmitri G; Thøgersen, Jan; Weidenspointner, Georg; White, Thomas A; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N; Küpper, Jochen

    2014-01-01

    We give a detailed account of the theoretical analysis and the experimental results of an x-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett. 112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i. e., picometers and femtoseconds, using x-ray free-electron lasers.

  1. Power delivery of free electron laser light by hollow glass waveguides.

    Science.gov (United States)

    Matsuura, Y; Matsuura, K; Harrington, J A

    1996-09-20

    Hollow glass waveguides are used to deliver free electron laser (FEL) energy for applications in medicine and laser surgery. The hollow guides, optimized for the delivery of 6.45-μm FEL radiation, exhibited losses for the 1000-μm bore as low as 0.39 dB/m when the guide was straight and 1.75 dB/m when bent to a radius of 25 cm. Hollow glass guides are flexible, and their broadband capability provides an ideal fiber optic for the tunable FEL.

  2. Ultrafast Coherent Diffraction Imaging with X-ray Free-Electron Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, H N; Bajt, S; Barty, A; Benner, W; Bogan, M; Frank, M; Hau-Riege, S; London, R; Marchesini, S; Spiller, E; Szoke, A; Woods, B; Boutet, S; Hodgson, K; Hajdu, J; Bergh, M; Burmeister, F; Caleman, C; Huldt, G; Maia, F; Seibert, M M; der Spoel, D v

    2006-08-22

    The ultrafast pulses from X-ray free-electron lasers will enable imaging of non-periodic objects at near-atomic resolution [1, Neutze]. These objects could include single molecules, protein complexes, or virus particles. The specimen would be completely destroyed by the pulse in a Coulomb explosion, but that destruction will only happen after the pulse. The scattering from the sample will give structural information about the undamaged object. There are many technical challenges that must be addressed before carrying out such experiments at an XFEL, which we are doing so with experiments at FLASH, the soft-X-ray FEL at DESY.

  3. Free-Electron Laser as a Driver for a Resonant Cavity at 35 GHz

    Science.gov (United States)

    Lefevre, T.; Gardelle, J.; Rullier, J. L.; Vermare, C.; Donohue, J. T.; Meurdesoif, Y.; Lidia, S. M.

    2000-02-01

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity.

  4. Single-shot measurement of free-electron laser polarization at SDUV-FEL

    CERN Document Server

    Feng, Lie; Zhang, Tong; Feng, Chao; Chen, Jianhui; Wang, Xingtao; Lan, Taihe; Shen, Lei; Zhang, Wenyan; Yao, Haifeng; Liu, Xiaoqing; Liu, Bo; Wang, Dong

    2014-01-01

    In this paper, a division-of-amplitude photopolarimeter (DOAP) for measuring the polarization state of free-electron laser (FEL) pulse is described. The incident FEL beam is divided into four separate beams, and four Stokes parameters can be measured in a single-shot. In the crossed-planar undulators experiment at Shanghai deep ultraviolet FEL test facility, this DOAP instrument constructed in house responses accurately and timely while the polarization-state of fully coherent FEL pulses are switched, which is helpful for confirming the crossed-planar undulators technique for short-wavelength FELs.

  5. Dissociative multiple ionization of diatomic molecules by extreme-ultraviolet free-electron-laser pulses

    DEFF Research Database (Denmark)

    Madsen, Lars Bojer; Leth, Henriette Astrup

    2011-01-01

    Nuclear dynamics in dissociative multiple ionization processes of diatomic molecules exposed to extreme-ultraviolet free-electron-laser pulses is studied theoretically using the Monte Carlo wave packet approach. By simulated detection of the emitted electrons, the model reduces a full propagation...... of the system to propagations of the nuclear wave packet in one specific electronic charge state at a time. Suggested ionization channels can be examined, and kinetic energy release spectra for the nuclei can be calculated and compared with experiments. Double ionization of O2 is studied as an example, and good...

  6. Gain enhancement in a two-frequency high-gain waveguide free-electron laser

    CERN Document Server

    Lefèvre, T; Rullier, J L; Gouard, P; Donohue, J T

    2002-01-01

    In a waveguide monomode free-electron laser (FEL), two resonant frequencies can be amplified by the electron beam. At the CEA/CESTA facility, single-pass high-gain FEL experiments have been performed over the last five years using relativistic electron beams provided by induction linacs. Most of the work was done in the amplifier regime (at the higher frequency) with the aim of producing a 35 GHz bunched beam. However, super-radiant measurements were also made and have shown that the FEL gain at the upper frequency is higher than in the amplifier regime and may be driven by the lower frequency FEL interaction.

  7. Matter under extreme conditions probed by a seeded free-electron-laser

    Energy Technology Data Exchange (ETDEWEB)

    Bencivenga, F.; Principi, E.; Cucini, R.; Danailov, M. B.; Demidovich, A.; D’Amico, F.; Di Fonzo, S.; Gessini, A.; Kurdi, N.; Mahne, N.; Raimondi, L.; Zangrando, M.; Masciovecchio, C. [Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163,5 in AREA Science Park, 34149 Basovizza (Italy); Giangrisostomi, E.; Battistoni, A.; Svetina, C. [Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163,5 in AREA Science Park, 34149 Basovizza (Italy); Dipartimento di Fisica, Universita di Trieste, Piazzale Europa, 34127 Trieste (Italy); Di Cicco, A.; Gunnella, R.; Hatada, K. [CNISM, Dipartimento di Fisica, Universita' di Camerino, Via Madonna delle Carceri, 62032 Camerino (Italy); Filipponi, A. [Dipartimento di Scienze Fisiche e Chimiche, Universita' dell’Aquila, Via Vetoio, 67100 L’Aquila (Italy); and others

    2015-08-17

    FERMI is the first user dedicated seeded free-electron-laser (FEL) working in the extreme ultraviolet (XUV) and soft x-ray range. The EIS-TIMEX experimental end-station was availabe to external users since from the beginning of the user operation of the facility, in Dicember 2012. EIS-TIMEX has been conceived to exploit the unique properties of the FERMI source to study matter under extreme and metastable thermodynamic conditions. We hereby report on its basic parameters and applications, which includes very low jitter (i.e., high time resolution) pump-probe measurements.

  8. Femtosecond x-ray free electron laser pulse duration measurement from spectral correlation function

    Directory of Open Access Journals (Sweden)

    A. A. Lutman

    2012-03-01

    Full Text Available We present a novel method for measuring the duration of femtosecond x-ray pulses from self-amplified spontaneous emission free electron lasers by performing statistical analysis in the spectral domain. Analytical expressions of the spectral correlation function were derived in the linear regime to extract both the pulse duration and the spectrometer resolution. Numerical simulations confirmed that the method can be also used in the nonlinear regime. The method was demonstrated experimentally at the Linac Coherent Light Source by measuring pulse durations down to 13 fs FWHM.

  9. Intense ultrashort pulse generation using the JAERI far-infrared free electron laser

    CERN Document Server

    Nagai, R; Nishimori, N; Kikuzawa, N; Sawamura, M; Minehara, E J

    2002-01-01

    An intense ultrashort optical pulse has been quasi-continuously generated using a superconducting RF linac-based free-electron laser at a wavelength of 22.5 mu m. The pulse shape and width are measured by second-order optical autocorrelation with a birefringent Te crystal. At synchronism of the optical resonator, the pulse shape is a smooth single pulse with an FWHM width of 255 fs and energy of 74 mu J. A train of subpulses is developed by increasing the desynchronism of the optical resonator. The measured results are in good agreement with numerical simulation.

  10. Improved performance of the JAERI injection and free electron laser system

    CERN Document Server

    Nishimori, N; Hajima, R; Shizuma, T; Sawamura, M; Kikuzawa, N; Minehara, E J

    2000-01-01

    Several modifications have been made for the JAERI Free Electron Laser (FEL) system in order to extract greater average lasing power. The electron gun was improved to produce an electron beam with 1 ns pulse width, 600 mA peak current, amplitude fluctuation less than 1% and timing jitter less than 0.1 ns. In addition, the 180 deg. bending arc was modified to match the beam envelope inside the undulator. After these modifications, we obtained an FEL power of 180 W in macro-pulse average at wavelength of 23 mu m.

  11. Imaging the He$_2$ quantum halo state using a free electron laser

    CERN Document Server

    Zeller, S; Voigtsberger, J; Kalinin, A; Schottelius, A; Schober, C; Waitz, M; Sann, H; Hartung, A; Bauer, T; Pitzer, M; Trinter, F; Goihl, C; Janke, C; Richter, M; Kastirke, G; Weller, M; Czasch, A; Kitzler, M; Braune, M; Grisenti, R E; Schöllkopf, W; Schmidt, L Ph H; Schöffer, M; Williams, J B; Jahnke, T; Dörner, R

    2016-01-01

    We report on coulomb explosion imaging of the wavefunction of the quantum halo system He$_2$. Each atom of this system is ionized by tunnelionization in a femto second laser pulse and in a second experiment by single photon ionization employing a free electron laser. We visualize the exponential decay of the probability density of the tunneling particle over distance for over two orders of magnitude up to an internuclear distance of 250 \\r{A}. By fitting the slope of the density in the tunneling regime we obtain a binding energy of 151.9 $\\pm$ 13.3 neV, which is in agreement with most recent calculations.

  12. Free electron laser induced two-photon photoconductivity in Hg1-xCdxTe

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Beijing free electron laser (BFEL) has been employed for the first time to study the nonlinear photoconductivity characteristics of the typical infrared photoelectronic material Hg1-xCdxTe. Taking advantage of the high photon flux density of BFEL, we have investigated the photoconductivity characteristics in Hg1-xCdxTe induced by two-photon absorption by means of the photoconductivity technique, observed the photoconductivity signals saturation, and studied the two-photon photoconductivity characteristics on different bias voltages across the sample.

  13. The project of the high power free electron laser based on the race-track microtron-recuperator

    Science.gov (United States)

    Vinokurov, N. A.; Gavrilov, N. G.; Gorniker, E. I.; Kulipanov, G. N.; Kuptsov, I. V.; Kurkin, G. Ya.; Erg, G. I.; Levashov, Yu. I.; Oreshkov, A. D.; Petrov, S. P.; Petrov, V. M.; Pinayev, I. V.; Popik, V. M.; Sedlyarov, I. K.; Shaftan, T. V.; Skrinsky, A. N.; Sokolov, A. S.; Veshcherevich, V. G.; Vobly, P. D.

    1995-02-01

    To provide a user facility for the Siberian Centre of Photochemical Researches in Novosibirsk a high power free electron laser is under construction. The project status and installation are described.

  14. Chirped seeded free-electron lasers: self-standing light sources for two-colour pump-probe experiments

    CERN Document Server

    De Ninno, Giovanni; Mahieu, Benoit

    2012-01-01

    We demonstrate the possibility to run a single-pass free-electron laser in a new dynamical regime, which can be exploited to perform two-colour pump-probe experiments in the VUV/X-ray domain, using the free-electron laser emission both as a pump and as a probe. The studied regime is induced by triggering the free-electron laser process with a powerful laser pulse, carrying a significant and adjustable frequency chirp. As a result, the emitted light is eventually split in two sub-pulses, whose spectral and temporal separations can be independently controlled. We provide a theoretical description of this phenomenon, which is found in good agreement with experiments performed on the FERMI@Elettra free-electron laser.

  15. Near-field optical microscopy with an infra-red free electron laser applied to cancer diagnosis

    Science.gov (United States)

    Smith, A. D.; Siggel-King, M. R. F.; Holder, G. M.; Cricenti, A.; Luce, M.; Harrison, P.; Martin, D. S.; Surman, M.; Craig, T.; Barrett, S. D.; Wolski, A.; Dunning, D. J.; Thompson, N. R.; Saveliev, Y.; Pritchard, D. M.; Varro, A.; Chattopadhyay, S.; Weightman, P.

    2013-02-01

    We show that the combination of a scanning near field optical microscope and an infra-red free electron laser yields chemical images with sub-cellular spatial resolution that have the potential to provide a diagnostic for oesophageal adenocarcinoma.

  16. First observation of self-amplified spontaneous emission in a free-electron laser at 109 nm wavelength

    Science.gov (United States)

    Saldin; Sandner; Sanok; Schlarb; Schmidt; Schmuser; Schneider; Schneidmiller; Schreiber; Schreiber; Schutt; Sekutowicz; Serafini; Sertore; Setzer; Simrock; Sonntag; Sparr; Stephan; Sytchev; Tazzari; Tazzioli; Tigner; Timm; Tonutti; Trakhtenberg

    2000-10-30

    We present the first observation of self-amplified spontaneous emission (SASE) in a free-electron laser (FEL) in the vacuum ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approximately 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width, and intensity fluctuations, are all consistent with the present models for SASE FELs.

  17. Shack-Hartmann Electron Densitometer (SHED): An Optical System for Diagnosing Free Electron Density in Laser-Produced Plasmas

    Science.gov (United States)

    2016-11-01

    the free electron density in USPL-created plasmas are limited in the number of space-time dimensions that can be measured simultaneously. One...profile, and c) parabolic density profile 2.1 Cylindrical Geometry This geometry is a first -order approximation of that created in the...Free Electron Density in Laser-Produced Plasmas by Anthony R Valenzuela Approved for public release; distribution is

  18. Building block diode laser concept for high brightness laser output in the kW range and its applications

    Science.gov (United States)

    Ferrario, Fabio; Fritsche, Haro; Grohe, Andreas; Hagen, Thomas; Kern, Holger; Koch, Ralf; Kruschke, Bastian; Reich, Axel; Sanftleben, Dennis; Steger, Ronny; Wallendorf, Till; Gries, Wolfgang

    2016-03-01

    The modular concept of DirectPhotonics laser systems is a big advantage regarding its manufacturability, serviceability as well as reproducibility. By sticking to identical base components an economic production allows to serve as many applications as possible while keeping the product variations minimal. The modular laser design is based on single emitters and various combining technics. In a first step we accept a reduction of the very high brightness of the single emitters by vertical stacking several diodes in fast axis. This can be theoretically done until the combined fast axis beam quality is on a comparable level as the individual diodes slow axis beam quality without loosing overall beam performance after fiber coupling. Those stacked individual emitters can be wavelength stabilized by an external resonator, providing the very same feedback to each of those laser diodes which leads to an output power of about 100 W with BPP of stacking those building blocks using the very same dense spectral combing technique up to multi kW Systems without further reduction of the BPP. The 500 W building blocks are consequently designed in a way that they feature a high flexibility with regard to their emitting wavelength bandwidth. Therefore, new wavelengths can be implemented by only exchanging parts and without any additional change of the production process. This design principal theoretically offers the option to adapt the wavelength of those blocks to any applications, from UV, visible into the far IR as long as there are any diodes commercially available. This opens numerous additional applications like laser pumping, scientific applications, materials processing such as cutting and welding of copper aluminum or steel and also medical application. Typical operating at wavelengths in the 9XX nm range, these systems are designed for and mainly used in cutting and welding applications, but adapted wavelength ranges such as 793 nm and 1530 nm are also offered. Around 15

  19. Multi-kW high-brightness fiber coupled diode laser based on two dimensional stacked tailored diode bars

    Science.gov (United States)

    Bayer, Andreas; Unger, Andreas; Köhler, Bernd; Küster, Matthias; Dürsch, Sascha; Kissel, Heiko; Irwin, David A.; Bodem, Christian; Plappert, Nora; Kersten, Maik; Biesenbach, Jens

    2016-03-01

    The demand for high brightness fiber coupled diode laser devices in the multi kW power region is mainly driven by industrial applications for materials processing, like brazing, cladding and metal welding, which require a beam quality better than 30 mm x mrad and power levels above 3kW. Reliability, modularity, and cost effectiveness are key factors for success in the market. We have developed a scalable and modular diode laser architecture that fulfills these requirements through use of a simple beam shaping concept based on two dimensional stacking of tailored diode bars mounted on specially designed, tap water cooled heat sinks. The base element of the concept is a tailored diode laser bar with an epitaxial and lateral structure designed such that the desired beam quality in slow-axis direction can be realized without using sophisticated beam shaping optics. The optical design concept is based on fast-axis collimator (FAC) and slow-axis collimator (SAC) lenses followed by only one additional focusing optic for efficient coupling into a 400 μm fiber with a numerical aperture (NA) of 0.12. To fulfill the requirements of scalability and modularity, four tailored bars are populated on a reduced size, tap water cooled heat sink. The diodes on these building blocks are collimated simply via FAC and SAC. The building blocks can be stacked vertically resulting in a two-dimensional diode stack, which enables a compact design of the laser source with minimum beam path length. For a single wavelength, up to eight of these building blocks, implying a total of 32 tailored bars, can be stacked into a submodule, polarization multiplexed, and coupled into a 400 μm, 0.12NA fiber. Scalability into the multi kW region is realized by wavelength combining of replaceable submodules in the spectral range from 900 - 1100 nm. We present results of a laser source based on this architecture with an output power of more than 4 kW and a beam quality of 25 mm x mrad.

  20. Compact X-ray free-electron laser based on an optical undulator

    Energy Technology Data Exchange (ETDEWEB)

    Bacci, A.; Maroli, C. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Petrillo, V. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Universita degli Studi di Milano, Via Celoria 16, 20133 Milan (Italy)], E-mail: Petrillo@mi.infn.it; Rossi, A.R.; Serafini, L. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Tomassini, P. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Universita degli Studi di Pisa, Via Buonarroti, 256127 Pisa (Italy)

    2008-03-21

    The interaction between a very high-brightness electron beam and a relativistically intense optical laser pulse produces X-rays via coherent Thomson back scattering with FEL collective amplification. The phenomenon is, however, very selective, so that the characteristics of both electron and laser beam must satisfy tight requirements in terms of beam current, emittance, energy spread and laser amplitude stability within the pulse. The three-dimensional equations governing the radiation phenomena have been studied in both linear and non-linear regime and solved numerically for the particularly interesting values of wavelengths of 1 A, 1 and 12 nm. The performance of the collective Thomson source has been compared with that of an equivalent static undulator. A set of scaling laws ruling the phenomenon is also presented.

  1. Evaluation of the cone-shaped pickup performance for low charge sub-10 fs arrival-time measurements at free electron laser facilities

    Directory of Open Access Journals (Sweden)

    Aleksandar Angelovski

    2015-01-01

    Full Text Available An evaluation of the cone-shaped pickup performance as a part of the high bandwidth bunch arrival-time monitors (BAMs for a low charge sub-10 fs arrival-time measurements is presented. Three sets of pickups are installed at the free electron laser FLASH at Deutsches Elektronen-Synchrotron, the quasi-cw SRF accelerator ELBE at the Helmholtz-Zentrum Dresden-Rossendorf and the SwissFEL injector test facility at Paul Scherrer Institute. Measurements and simulations are in good agreement and the pickups fulfill the design specifications. Utilizing the high bandwidth BAM with the cone-shaped pickups, an improvement of the signal slope by a factor of 10 is demonstrated at ELBE compared to the BAM with a low bandwidth.

  2. The European X-ray Free-Electron Laser: toward an ultra-bright, high repetition-rate x-ray source

    Institute of Scientific and Technical Information of China (English)

    M.Altarelli

    2015-01-01

    The status of the European X-ray Free-Electron Laser(European XFEL), under construction near Hamburg, Germany, is described. The start of operations of the LCLS at SLAC and of SACLA in Japan has already produced impressive scientific results. The European XFEL facility is powered by a 17.5 Ge V superconducting linear accelerator that,compared to these two operating facilities, will generate two orders of magnitude more pulses per second, up to 27 000.It can therefore support modes of operation switching the beam up to 30 times per second among three different experiments, providing each of them with thousands of pulses per second. The scientific possibilities opened up by these capabilities are briefly described, together with the current instrumental developments(in optics, detectors, lasers,etc.) that are necessary to implement this program.

  3. Applied research using a 30 GHz free-electron maser: Experimental study of interacton of high-power pulsed radiation with metals

    Science.gov (United States)

    Baev, V. G.; Vdovin, V. A.; Vikharev, A. A.; Ginzburg, N. S.; Golubev, I. I.; Golubykh, S. M.; Zaitsev, N. I.; Kaminsky, A. K.; Kovalev, Yu. A.; Kozlov, A. P.; Kratko, A. F.; Kryachko, I. A.; Kuzikov, S. V.; Lesnikovich, A. I.; Milevich, I. A.; Perel'shtein, E. A.; Peskov, N. Yu.; Petelin, M. I.; Sedykh, S. N.; Tyutyunnikov, S. I.; Fedotova, Yu. A.

    2012-01-01

    We describe a facility for testing the properties of different objects affected by a sequence of highpower pulses of the microwave electromagnetic field. The facility performance is implemented due to the power level and stability of the single-mode generation of a free electron maser with an output frequency of 30 GHz, which have been achieved at the Joint Institute for Nuclear Research and the Institute of Applied Physics of the Russian Academy of Sciences. This paper describes the experiments on studying of the thermal fatigue of the copper surface in a test cavity, which models the thermal regime of the accelerating structure of the CLIC project (CERN), as well as the experiments on irradiation of biological tissues, metal films, and nanoclusters.

  4. Direct and secondary nuclear excitation with x-ray free-electron lasers

    CERN Document Server

    Gunst, Jonas; Kumar, Naveen; Keitel, Christoph H; Pálffy, Adriana

    2015-01-01

    The direct and secondary nuclear excitation produced by an x-ray free electron laser when interacting with a solid-state nuclear target is investigated theoretically. When driven at the resonance energy, the x-ray free electron laser can produce direct photoexcitation. However, the dominant process in that interaction is the photoelectric effect producing a cold and very dense plasma in which also secondary processes such as nuclear excitation by electron capture may occur. We develop a realistic model to quantify the temporal dynamics of the plasma and the magnitude of the secondary excitation therein. Numerical results show that depending on the nuclear transition energy and the temperature and charge states reached in the plasma, secondary nuclear excitation by electron capture may dominate the direct photoexcitation by several orders of magnitude, as it is the case for the 4.8 keV transition from the isomeric state of $^{93}$Mo, or it can be negligible, as it is the case for the 14.4 keV M\\"ossbauer trans...

  5. The effects of slippage and diffraction in long wavelength operation of a free electron laser

    Science.gov (United States)

    Zhulin, V. I.; Haselhoff, E. H.; van Amersfoort, P. W.

    1995-01-01

    The Free-Electron Laser user facility FELIX produces picosecond optical pulses in the wavelength range of 5 110 μm. The proposed installation of a new undulator with a larger magnetic period would allow extension towards considerably longer wavelengths. This would result in the production of extremely short, far-infrared pulses, with a duration of a single optical period or even less. In order to investigate the pulse propagation for free-electron lasers operating in the long wavelength limit, a three-dimensional simulation code was developed. Using the FELIX parameters, with the addition of a long-period undulator, the effects of slippage, diffraction losses, changes in the filling factor, as well as the effects of the optical cavity geometry were studied for wavelengths up to 300 μm, with electron pulses in the ps regime. It is shown that slippage effects are less restrictive for long wavelength operation than the increasing losses due to optical beam diffraction.

  6. Visible-infrared self-amplified spontaneous emission amplifier free electron laser undulator

    Science.gov (United States)

    Carr, Roger; Cornacchia, Max; Emma, Paul; Nuhn, Heinz-Dieter; Poling, Ben; Ruland, Robert; Johnson, Erik; Rakowsky, George; Skaritka, John; Lidia, Steve; Duffy, Pat; Libkind, Marcus; Frigola, Pedro; Murokh, Alex; Pellegrini, Claudio; Rosenzweig, James; Tremaine, Aaron

    2001-12-01

    The visible-infrared self-amplified spontaneous emission amplifier (VISA) free electron laser (FEL) is an experimental device designed to show self-amplified spontaneous emission (SASE) to saturation in the near infrared to visible light energy range. It generates a resonant wavelength output from 800-600 nm, so that silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is designed to show how SASE FEL theory corresponds with experiment in this wavelength range, using an electron beam with emittance close to that planned for the future Linear Coherent Light Source at SLAC. VISA comprises a 4 m pure permanent magnet undulator with four 99 cm segments, each of 55 periods, 18 mm long. The undulator has distributed focusing built into it, to reduce the average beta function of the 70-85 MeV electron beam to about 30 cm. There are four FODO cells per segment. The permanent magnet focusing lattice consists of blocks mounted on either side of the electron beam, in the undulator gap. The most important undulator error parameter for a free electron laser is the trajectory walk-off, or lack of overlap of the photon and electron beams. Using pulsed wire magnet measurements and magnet shimming, we were able to control trajectory walk-off to less than +/-50 μm per field gain length.

  7. Optical synchronization of a free-electron laser with femtosecond precision

    Energy Technology Data Exchange (ETDEWEB)

    Loehl, F.

    2009-09-15

    High-gain free-electron lasers (FELs) are capable of generating sub-10 fs long light pulses. In order to take full advantage of these extremely short light pulses in time-resolved experiments, synchronization with a so far unprecedented timing accuracy is required. Within this thesis, an optical synchronization system providing sub-10 fs stability has been developed and was implemented at the ultra-violet and soft X-ray free-electron laser FLASH at DESY, Hamburg. The system uses a mode-locked laser as a timing reference. The laser pulses are distributed via length stabilized optical fiber-links to the remote locations. A key feature of the system is a bunch arrival-time monitor detecting the electron bunch arrival-time with an unrivaled resolution of 6 fs. A feedback system based on the arrival-time monitor was established, improving the arrival-time fluctuations from 200 fs in the unstabilized case to 25 fs with active feedback. In order to achieve the high peak current of several thousand amperes required for the FEL process, the electron bunches are longitudinally compressed in two magnetic chicanes. A second feedback system was developed stabilizing the bunch compression process based on measurements of diffraction radiation. The combination of both feedback systems improves the stability of the FEL radiation significantly. (orig.)

  8. Compositional change in human enamel irradiated with MIR free electron laser

    Institute of Scientific and Technical Information of China (English)

    YANGXueping; LiGuangcheng; HuangYuying; DONGYanmei; GAOXuejun; LUIN

    2001-01-01

    The purpose of this study was to investigate compositional changes in human enamel irradiated with the free electron laser (FEL).The exposure on dental enamel at the wavelength of 9.64μm was observed with the Beijing free electron laser.The distribution of elements in the irradiated or non-irradiated enamel was measured by scanning electron microscope (SEM) with energy-dispersive spectroscopy and synchrotron radiation X-ray fluorescence(SRXRF) in Beijing Synchrotron Radiation Facility (BSRF).The results showed that the P/Ca ratio in the ablation region of enamel at the maximum wavelength of infrared absorption of enalmel at the maximum wavelength of infrared absorption was obviously smaller than that at the non-maximum wavelength.In the ablation region the ratios of P/Ca and Ca/Sr were smaller than those in the non-ablation region.The distribution of P,Ca and Sr in the ablation region were heterogeneous due to the element change caused by FEL irradiation.

  9. Microbunching-instability-induced sidebands in a seeded free-electron laser

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2016-05-01

    Full Text Available Measurements of the multishot-averaged, soft x-ray, self-seeding spectrum at the LCLS free-electron laser often have a pedestal-like distribution around the seeded wavelength, which limits the spectral purity and can negatively affect some user applications not employing a post-undulator monochromator. In this paper, we study the origins of such pedestals, focusing on longitudinal phase space modulations produced by the microbunching instability upstream of the free-electron laser (FEL undulator. We show from theory and numerical simulation that both energy and density modulations can induce sidebands in a high-gain, seeded FEL whose fractional strength typically grows as the square of the undulator length. The results place a tight constraint on the longitudinal phase space uniformity of the electron beam for a seeded FEL, possibly requiring the amplitude of long-wavelength modulations to be much smaller than the typical incoherent energy spread if the output sideband power is to remain only a couple percent or less of the amplified seed power.

  10. Visible-infrared self-amplified spontaneous emission amplifier free electron laser undulator

    Directory of Open Access Journals (Sweden)

    Roger Carr

    2001-12-01

    Full Text Available The visible-infrared self-amplified spontaneous emission amplifier (VISA free electron laser (FEL is an experimental device designed to show self-amplified spontaneous emission (SASE to saturation in the near infrared to visible light energy range. It generates a resonant wavelength output from 800–600 nm, so that silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is designed to show how SASE FEL theory corresponds with experiment in this wavelength range, using an electron beam with emittance close to that planned for the future Linear Coherent Light Source at SLAC. VISA comprises a 4 m pure permanent magnet undulator with four 99 cm segments, each of 55 periods, 18 mm long. The undulator has distributed focusing built into it, to reduce the average beta function of the 70–85 MeV electron beam to about 30 cm. There are four FODO cells per segment. The permanent magnet focusing lattice consists of blocks mounted on either side of the electron beam, in the undulator gap. The most important undulator error parameter for a free electron laser is the trajectory walk-off, or lack of overlap of the photon and electron beams. Using pulsed wire magnet measurements and magnet shimming, we were able to control trajectory walk-off to less than ±50 μm per field gain length.

  11. Terawatt x-ray free-electron-laser optimization by transverse electron distribution shaping

    Directory of Open Access Journals (Sweden)

    C. Emma

    2014-11-01

    Full Text Available We study the dependence of the peak power of a 1.5 Å Terawatt (TW, tapered x-ray free-electron laser (FEL on the transverse electron density distribution. Multidimensional optimization schemes for TW hard x-ray free-electron lasers are applied to the cases of transversely uniform and parabolic electron beam distributions and compared to a Gaussian distribution. The optimizations are performed for a 200 m undulator and a resonant wavelength of λ_{r}=1.5  Å using the fully three-dimensional FEL particle code genesis. The study shows that the flatter transverse electron distributions enhance optical guiding in the tapered section of the undulator and increase the maximum radiation power from a maximum of 1.56 TW for a transversely Gaussian beam to 2.26 TW for the parabolic case and 2.63 TW for the uniform case. Spectral data also shows a 30%–70% reduction in energy deposited in the sidebands for the uniform and parabolic beams compared with a Gaussian. An analysis of the transverse coherence of the radiation shows the coherence area to be much larger than the beam spotsize for all three distributions, making coherent diffraction imaging experiments possible.

  12. Start-to-end simulations for a seeded harmonic generation free electron laser

    Directory of Open Access Journals (Sweden)

    S. Thorin

    2007-11-01

    Full Text Available This paper shows how the MAX linac injector and transport system can be efficiently retuned to suit free electron laser (FEL performance. In a collaboration between MAX-lab and BESSY, a seeded harmonic generation free electron laser is being constructed at MAX-lab. The setup uses the existing MAX-lab facility upgraded with a new low emittance photocathode gun, a Ti∶Sa 266 nm laser system used for both the gun and seeding and an FEL undulator system. To produce the high quality electron beam needed, it is shown how the magnet optics in an achromatic dogleg can be tuned to create an optimum bunch compression and how a good quality beam can be maintained through the beam transport and delivered to the FEL undulators. In extensive start-to-end simulations from the cathode of the gun to the generation of photons in the undulators, FEL performance and stability has been calculated using simulation tools like ASTRA, ELEGANT, and GENESIS. This has been done for both the third and fifth harmonic of the seed laser. The results from the calculation are 30 fs light pulses with a power of 11 MW at 88 nm and 1.4 MW at 53 nm.

  13. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenting; Nogly, Przemyslaw; Rheinberger, Jan; Kick, Leonhard M.; Gati, Cornelius; Nelson, Garrett; Deupi, Xavier; Standfuss, Jörg; Schertler, Gebhard; Panneels, Valérie, E-mail: valerie.panneels@psi.ch [Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI (Switzerland)

    2015-06-27

    A new batch preparation method is presented for high-density micrometre-sized crystals of the G protein-coupled receptor rhodopsin for use in time-resolved serial femtosecond crystallography at an X-ray free-electron laser using a liquid jet. Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.

  14. High-brightness picosecond ion beam source based on BNL Terawatt CO2 laser: Proof-of-principle experiments

    Energy Technology Data Exchange (ETDEWEB)

    Shkolnikov, Peter

    2012-10-04

    Under the continuing DOE support, we have: o assembled the basic experiment setup and then continued expanding it to include diverse diagnostics and to accommodate gas jet targets in addition to metal foils; o conducted an extensive study of our novel laser, significantly enhanced laser beam diagnostics, and improved relevant laser parameters; o turned our experiments into a truly international endeavor with active collaboration of close to 20 researchers in US, UK, and Germany; o conducted the first ever experiments with proton and ion acceleration by lasers interacting with overcritical plasma of gas jets; o for the first time directly observed radiation pressure acceleration of protons, including quasi-monoenergetic spectra promising for future applications; o for the first time directly observed quasi-stable, bubble-like plasma structures that likely evolved from relativistic laser-plasma solitons (post-solitons). Thus, we have confirmed a strong potential of a picosecond TW CO2 laser as a research tool in laser-plasma science and as a promising vehicle for future applications of laser ion acceleration. This has led to apparent increase of the interest in mid-IR laser ion acceleration. In particular, another major research group began extensive proton acceleration experiments with their own CO2 laser at UCLA. As a result, the mechanisms responsible for laser proton acceleration in gas jets have become somewhat clearer. It is also important to note that modest DOE funding played the role of a seed support ensuring the formation of a multinational research team, whose members contributed its time and equipment with value well in excess of that seed amount.

  15. Generation of High Brightness Electron Beams via Ionization Induced Injection by Transverse Colliding Lasers in a Beam-Driven Plasma Wakefield Accelerator

    CERN Document Server

    Li, F; Xu, X L; Zhang, C J; Yan, L X; Du, Y C; Huang, W H; Cheng, H B; Tang, C X; Lu, W; Joshi, C; Mori, W B; Gu, Y Q

    2013-01-01

    The production of ultra-bright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional (3D) particle-in-cell (PIC) simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is much reduced and the injection is localized along the propagation axis of the wake. This minimizes both the initial 'thermal' emittance and the emittance growth due to transverse phase mixing. 3D PIC simulations show that ultra-short (around 8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes respectively and a brightness greater than 1.7*10e19 A rad-2 m-2 can be obtained for realistic parameters.

  16. Three-dimensional, time-dependent simulation of free-electron lasers with planar, helical, and elliptical undulators

    Science.gov (United States)

    Freund, H. P.; van der Slot, P. J. M.; Grimminck, D. L. A. G.; Setija, I. D.; Falgari, P.

    2017-02-01

    Free-electron lasers (FELs) have been built ranging in wavelength from long-wavelength oscillators using partial wave guiding through ultraviolet through hard x-ray that are either seeded or start from noise. In addition, FELs that produce different polarizations of the output radiation ranging from linear through elliptic to circular polarization are currently under study. In this paper, we develop a three-dimensional, time-dependent formulation that is capable of modeling this large variety of FEL configurations including different polarizations. We employ a modal expansion for the optical field, i.e., a Gaussian expansion with variable polarization for free-space propagation. This formulation uses the full Newton–Lorentz force equations to track the particles through the optical and magnetostatic fields. As a result, arbitrary three-dimensional representations for different undulator configurations are implemented, including planar, helical, and elliptical undulators. In particular, we present an analytic model of an APPLE-II undulator to treat arbitrary elliptical polarizations, which is used to treat general elliptical polarizations. To model oscillator configurations, and allow propagation of the optical field outside the undulator and interact with optical elements, we link the FEL simulation with the optical propagation code OPC. We present simulations using the APPLE-II undulator model to produce elliptically polarized output radiation, and present a detailed comparison with recent experiments using a tapered undulator configuration at the Linac Coherent Light Source. Validation of the nonlinear formation is also shown by comparison with experimental results obtained in the Sorgente Pulsata Auto-amplificata di Radiazione Coerente SASE FEL experiment at ENEA Frascati, a seeded tapered amplifier experiment at Brookhaven National Laboratory, and the 10 kW upgrade oscillator experiment at the Thomas Jefferson National Accelerator Facility.

  17. Selective Photothermolysis to target Sebaceous Glands: Theoretical Estimation of Parameters and Preliminary Results Using a Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Fernanda Sakamoto, Apostolos Doukas, William Farinelli, Zeina Tannous, Michelle D. Shinn, Stephen Benson, Gwyn P. Williams, H. Dylla, Richard Anderson

    2011-12-01

    The success of permanent laser hair removal suggests that selective photothermolysis (SP) of sebaceous glands, another part of hair follicles, may also have merit. About 30% of sebum consists of fats with copious CH2 bond content. SP was studied in vitro, using free electron laser (FEL) pulses at an infrared CH2 vibrational absorption wavelength band. Absorption spectra of natural and artificially prepared sebum were measured from 200 nm to 3000 nm, to determine wavelengths potentially able to target sebaceous glands. The Jefferson National Accelerator superconducting FEL was used to measure photothermal excitation of aqueous gels, artificial sebum, pig skin, human scalp and forehead skin (sebaceous sites). In vitro skin samples were exposed to FEL pulses from 1620 to 1720 nm, spot diameter 7-9.5 mm with exposure through a cold 4C sapphire window in contact with the skin. Exposed and control tissue samples were stained using H and E, and nitroblue tetrazolium chloride staining (NBTC) was used to detect thermal denaturation. Natural and artificial sebum both had absorption peaks near 1210, 1728, 1760, 2306 and 2346 nm. Laser-induced heating of artificial sebum was approximately twice that of water at 1710 and 1720 nm, and about 1.5x higher in human sebaceous glands than in water. Thermal camera imaging showed transient focal heating near sebaceous hair follicles. Histologically, skin samples exposed to {approx}1700 nm, {approx}100-125 ms pulses showed evidence of selective thermal damage to sebaceous glands. Sebaceous glands were positive for NBTC staining, without evidence of selective loss in samples exposed to the laser. Epidermis was undamaged in all samples. Conclusions: SP of sebaceous glands appears to be feasible. Potentially, optical pulses at {approx}1720 nm or {approx}1210 nm delivered with large beam diameter and appropriate skin cooling in approximately 0.1 s may provide an alternative treatment for acne.

  18. Direct Comparison of Brookhaven Reflectivity Measurements with Free-Electron Theory

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl L.F.

    2010-12-13

    The reflectivity at normal incidence of copper and aluminum samples was recently measured over a large frequency range at Brookhaven by one of us (JT). Then using the Kramers-Kroning integrals, and assuming the free-electron model of conductivity, the dependence of conductivity on frequency was obtained. The results seemed to suggest, for example, that the dc conductivities of the copper and evaporated aluminum samples are a factor of 3 lower than expected. We propose in this report, instead, directly fitting the free-electron model to the low frequency end of the reflectivity data. This fitting does not depend on the higher frequency results and on Kramers-Kronig integrations, but it does assume that the data at the low frequency end is sufficiently accurate. Note that for our LCLS wakefield studies, it is only over these (relatively) low frequencies that we need to know the electrical properties of the metals. The equations that relate reflectivity R with the free electron parameters dc conductivity {sigma} and relaxation time {tau} are: (1) {tilde {sigma}} = {sigma}/1-ikc{tau}; (2) {tilde n} = {radical} {tilde {epsilon}} = {radical}(1+4{pi}i{tilde k}c/{omega}); and (3) R = |{tilde n}-1/{tilde n} + 1|{sup 2}. The parameters are ac conductivity {tilde {sigma}}, index of refraction {tilde n}, dielectric constant {tilde {epsilon}}, and wave number k = {omega}/c, with {omega} frequency and c the speed of light. In Fig. 1 we show the ideal behavior of R for a reasonably good conducting metal, where {sigma} = 0.12 x 10{sup 17}/s and {tau} = 0.55 x 10{sup -14} s (solid line); these parameters are, respectively, 2% ({sigma}) and 20% ({tau}) of the nominal values for copper. The parameters were chosen so that the important features of R(k) could be seen easily in one plot. We see 3 distinct regions: (1) for low frequencies, k {approx}< 1/c{tau}, R continually decreases, with positive curvature, and with a low frequency asymptote of (1 - {radical}2kc/{pi}{sigma}); (2) for

  19. High Repetition Rate Electron Beam RF-Acceleration and Sub-Millimeter Wave Generation Via a Free Electron Laser.

    Science.gov (United States)

    1987-08-14

    Luhmann, Jr., "Enhancement of Traveling Wave Gain and Efficiency with a Phase Filter ," to be published in Tech. Digest IEDM N (1987). 8. Scientific...Unhmit:d - (i) Q.S. Wang, T.H. Kho, A.T. IUn, D.B. McDermott and N.C. Luhmann, Jr., "Enhancement of Traveling Wave Gain and Efficiency with a Phase ... Filter ," to be published in Proc. of the Twelfth IEEE Int. Conf. IR and MM-Waves (1987). (j) Q.S. Wang, T.H. Kho, A.T. Lin, D.B. McDermott and N.C

  20. Seeded free-electron and inverse free-electron laser techniques for radiation amplification and electron microbunching in the terahertz range

    Directory of Open Access Journals (Sweden)

    C. Sung

    2006-12-01

    Full Text Available A comprehensive analysis is presented that describes amplification of a seed THz pulse in a single-pass free-electron laser (FEL driven by a photoinjector. The dynamics of the radiation pulse and the modulated electron beam are modeled using the time-dependent FEL code, GENESIS 1.3. A 10-ps (FWHM electron beam with a peak current of 50–100 A allows amplification of a ∼1  kW seed pulse in the frequency range 0.5–3 THz up to 10–100 MW power in a relatively compact 2-m long planar undulator. The electron beam driving the FEL is strongly modulated, with some inhomogeneity due to the slippage effect. It is shown that THz microbunching of the electron beam is homogeneous over the entire electron pulse when saturated FEL amplification is utilized at the very entrance of an undulator. This requires seeding of a 30-cm long undulator buncher with a 1–3 MW of pump power with radiation at the resonant frequency. A narrow-band seed pulse in the THz range needed for these experiments can be generated by frequency mixing of CO_{2} laser lines in a GaAs nonlinear crystal. Two schemes for producing MW power pulses in seeded FELs are considered in some detail for the beam parameters achievable at the Neptune Laboratory at UCLA: the first uses a waveguide to transport radiation in the 0.5–3 THz range through a 2-m long FEL amplifier and the second employs high-gain third harmonic generation using the FEL process at 3–9 THz.

  1. Reflection of femtosecond pulses from soft X-ray free-electron laser by periodical multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ksenzov, D.; Grigorian, S.; Pietsch, U. [Faculty of Physics, University of Siegen (Germany); Hendel, S.; Bienert, F.; Sacher, M.D.; Heinzmann, U. [Faculty of Physics, University of Bielefeld (Germany)

    2009-08-15

    Recent experiments on a soft X-ray free-electron laser (FEL) source (FLASH in Hamburg) have shown that multilayers (MLs) can be used as optical elements for highly intense X-ray irradiation. An effort to find most appropriate MLs has to consider the femtosecond time structure and the particular photon energy of the FEL. In this paper we have analysed the time response of 'low absorbing' MLs (e.g. such as La/B{sub 4}C) as a function of the number of periods. Interaction of a pulse train of Gaussian shaped sub-pulses using a realistic ML grown by electron-beam evaporation technique has been analysed in the soft-X-ray range. The structural parameters of the MLs were obtained by reflectivity measurements at BESSY II and subsequent profile fittings. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  2. High gain harmonic generation free electron lasers enhanced by pseudoenergy bands

    Directory of Open Access Journals (Sweden)

    Takashi Tanaka

    2017-08-01

    Full Text Available We propose a new scheme for high gain harmonic generation free electron lasers (HGHG FELs, which is seeded by a pair of intersecting laser beams to interact with an electron beam in a modulator undulator located in a dispersive section. The interference of the laser beams gives rise to a two-dimensional modulation in the energy-time phase space because of a strong correlation between the electron energy and the position in the direction of dispersion. This eventually forms pseudoenergy bands in the electron beam, which result in efficient harmonic generation in HGHG FELs in a similar manner to the well-known scheme using the echo effects. The advantage of the proposed scheme is that the beam quality is less deteriorated than in other existing schemes.

  3. Emerging opportunities in structural biology with X-ray free-electron lasers

    Science.gov (United States)

    Schlichting, Ilme; Miao, Jianwei

    2012-01-01

    X-ray free-electron lasers (X-FELs) produce X-ray pulses with extremely brilliant peak intensity and ultrashort pulse duration. It has been proposed that radiation damage can be “outrun” by using an ultra intense and short X-FEL pulse that passes a biological sample before the onset of significant radiation damage. The concept of “diffraction-before-destruction” has been demonstrated recently at the Linac Coherent Light Source, the first operational hard X-ray FEL, for protein nanocrystals and giant virus particles. The continuous diffraction patterns from single particles allow solving the classical “phase problem” by the oversampling method with iterative algorithms. If enough data are collected from many identical copies of a (biological) particle, its three-dimensional structure can be reconstructed. We review the current status and future prospects of serial femtosecond crystallography (SFX) and single-particle coherent diffraction imaging (CDI) with X-FELs. PMID:22922042

  4. Spectrometer for Hard X-Ray Free Electron Laser Based on Diffraction Focusing

    CERN Document Server

    Kohn, V G; Vartanyants, I A

    2012-01-01

    X-ray free electron lasers (XFELs) generate sequences of ultra-short, spatially coherent pulses of x-ray radiation. We propose the diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of $\\Delta E/E\\approx 2\\times 10^{-6}$. This is much better than for most modern x-ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from the metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. We show that the DFS can be used in a wide energy range from 5 keV to 20 keV.

  5. Smith-Purcell free electron laser based on the semi-elliptical resonator

    Institute of Scientific and Technical Information of China (English)

    Meng xian-Zhu; Wang Ming-Hong; Ren Zhong-Min

    2011-01-01

    A novel Smith-Purcell (S-P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S-P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period,or adjusting the voltage of the electron beam. The present scheme has the following advantages: the semi-elliptical resonator can reflect all radiation with the emission angle θ and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.

  6. Theory of nonlinear harmonic generation in free-electron lasers with helical wigglers

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, G.; Saldin, E.; Schneidmiller, E.; Yurkov, M.

    2007-05-15

    CoherentHarmonicGeneration (CHG), and in particularNonlinearHarmonicGeneration (NHG), is of importance for both short wavelength Free-Electron Lasers (FELs), in relation with the achievement of shorter wavelengths with a fixed electron-beam energy, and high-average power FEL resonators, in relation with destructive effects of higher harmonics radiation on mirrors. In this paper we present a treatment of NHG from helical wigglers with particular emphasis on the second harmonic. Our study is based on an exact analytical solution of Maxwell's equations, derived with the help of a Green's function method. In particular, we demonstrate that nonlinear harmonic generation (NHG) fromhelicalwigglers vanishes on axis. Our conclusion is in open contrast with results in literature, that include a kinematical mistake in the description of the electron motion. (orig.)

  7. Development of High Performance Electron Beam Switching System for Swiss Free Electron Laser at PSI

    CERN Document Server

    Paraliev, M

    2012-01-01

    A compact X-ray Free Electron Laser (SwissFEL) is under development at the Paul Scherrer Institute. To increase facility efficiency the main linac will operate in two electron bunch mode. The two bunches are separated in time by 28 ns and sent to two undulator lines. The combination of two beam lines should produce short X-ray pulses covering wavelength range from 1 to 70 {\\AA} with submicron position stability. To separate the two bunches, a novel electron beam switching system is being developed. The total deflection is achieved with a combination of high Q-factor resonant deflector magnet, followed by a DC septum magnet. The shot-to-shot deflection stability of the entire switching system should be <+/-10 ppm in amplitude and +/-100 ps in time, values which present severe measurement difficulties. Deflection magnets requirements, development and results of the kicker prototype are presented.

  8. Sorting algorithms for single-particle imaging experiments at X-ray free-electron lasers.

    Science.gov (United States)

    Bobkov, S A; Teslyuk, A B; Kurta, R P; Gorobtsov, O Yu; Yefanov, O M; Ilyin, V A; Senin, R A; Vartanyants, I A

    2015-11-01

    Modern X-ray free-electron lasers (XFELs) operating at high repetition rates produce a tremendous amount of data. It is a great challenge to classify this information and reduce the initial data set to a manageable size for further analysis. Here an approach for classification of diffraction patterns measured in prototypical diffract-and-destroy single-particle imaging experiments at XFELs is presented. It is proposed that the data are classified on the basis of a set of parameters that take into account the underlying diffraction physics and specific relations between the real-space structure of a particle and its reciprocal-space intensity distribution. The approach is demonstrated by applying principal component analysis and support vector machine algorithms to the simulated and measured X-ray data sets.

  9. Towards jitter-free pump-probe measurements at seeded free electron laser facilities.

    Science.gov (United States)

    Danailov, Miltcho B; Bencivenga, Filippo; Capotondi, Flavio; Casolari, Francesco; Cinquegrana, Paolo; Demidovich, Alexander; Giangrisostomi, Erika; Kiskinova, Maya P; Kurdi, Gabor; Manfredda, Michele; Masciovecchio, Claudio; Mincigrucci, Riccardo; Nikolov, Ivaylo P; Pedersoli, Emanuele; Principi, Emiliano; Sigalotti, Paolo

    2014-06-02

    X-ray free electron lasers (FEL) coupled with optical lasers have opened unprecedented opportunities for studying ultrafast dynamics in matter. The major challenge in pump-probe experiments using FEL and optical lasers is synchronizing the arrival time of the two pulses. Here we report a technique that benefits from the seeded-FEL scheme and uses the optical seed laser for nearly jitter-free pump-probe experiments. Timing jitter as small as 6 fs has been achieved and confirmed by measurements of FEL-induced transient reflectivity changes of Si3N4 using both collinear and non-collinear geometries. Planned improvements of the experimental set-up are expected to further reduce the timing jitter between the two pulses down to fs level.

  10. Spectro-temporal shaping of seeded free-electron laser pulses

    CERN Document Server

    Gauthier, David; De Ninno, Giovanni; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Boyanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca; Mahieu, Benoît; Penco, Giuseppe

    2015-01-01

    We demonstrate the ability to control and shape the spectro-temporal content of extreme-ultraviolet (XUV) pulses produced by a seeded free-electron laser (FEL). The control over the spectro-temporal properties of XUV light was achieved by precisely manipulating the linear frequency chirp of the seed laser. Our results agree with existing theory, which allows retrieving the temporal properties (amplitude and phase) of the FEL pulse from measurements of the spectra as a function of the FEL operating parameters. Furthermore, we show the first direct evidence of the full temporal coherence of FEL light and generate Fourier limited pulses by fine-tuning the FEL temporal phase. The possibility to tailor the spectro-temporal content of intense short-wavelength pulses represents the first step towards efficient nonlinear optics in the XUV to X-ray spectral region and will enable precise manipulation of core-electron excitations using the methods of coherent quantum control.

  11. Absorber for wakefield interference management at the entrance of the wiggler of a free electron laser

    Science.gov (United States)

    Marchlik, Matthew; Biallas, George Herman

    2017-03-07

    A method for managing the broad band microwave and TeraHertz (THz) radiation in a free electron laser (FEL) having a wiggler producing power in the electromagnetic spectrum. The method includes placement of broadband microwave and TeraHertz (THz) radiation absorbers on the upstream end of the wiggler. The absorbers dampen the bounced back, broad band microwave and THz radiation returning from the surfaces outside the nose of the cookie-cutter and thus preventing broadening of the electron beam pulse's narrow longitudinal energy distribution. Broadening diminishes the ultimate laser power from the wiggler. The broadband microwave and THz radiation absorbers are placed on either side of the slot in the cookie-cutter that shapes the wake field wave of the electron pulse to the slot shape of the wiggler chamber aperture. The broad band microwave and THz radiation absorber is preferably a non-porous pyrolytic grade of graphite with small grain size.

  12. Statistical and coherence properties of radiation from X-ray free electron lasers

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2009-01-01

    We describe statistical and coherence properties of the radiation from x-ray free electron lasers (XFEL). It is shown that the X-ray FEL radiation before saturation is described with gaussian statistics. Particularly important is the case of the optimized X-ray FEL, studied in detail. Applying similarity techniques to the results of numerical simulations allowed us to find universal scaling relations for the main characteristics of an X-ray FEL operating in the saturation regime: efficiency, coherence time and degree of transverse coherence. We find that with an appropriate normalization of these quantities, they are functions of only the ratio of the geometrical emittance of the electron beam to the radiation wavelength. Statistical and coherence properties of the higher harmonics of the radiation are highlighted as well.

  13. Optical transition radiation measurements for the Los Alamos and Boeing Free-Electron Laser experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Feldman, D.W.; Apgar, S.A.; Calsten, B.E.; Fiorito, R.B.; Rule, D.W.

    1988-01-01

    Optical transition radiation (OTR) measurements of the electron-beam emittance have been performed at a location just before the wiggler in the Los Alamos Free-Electron Laser (FEL) experiment. Beam profiles and beam divergence patterns from a single macropulse were recorded simultaneously using two intensified charge-injection device (CID) television cameras and an optical beamsplitter. Both single-foil OTR and two-foil OTR interference experiments were performed. Preliminary results are compared to a reference variable quadrupole, single screen technique. New aspects of using OTR properties for pointing the e-beam on the FEL oscillator axis, as well as measuring e-beam emittance are addressed. 7 refs., 9 figs.

  14. Spatial and temporal coherence properties of single free-electron laser pulses

    CERN Document Server

    Singer, A; Mancuso, A P; Gerasimova, N; Yefanov, O M; Gulden, J; Gorniak, T; Senkbeil, T; Sakdinawat, A; Liu, Y; Attwood, D; Dziarzhytski, S; Mai, D D; Treusch, R; Weckert, E; Salditt, T; Rosenhahn, A; Wurth, W; Vartanyants, I A

    2015-01-01

    The experimental characterization of the spatial and temporal coherence properties of the free-electron laser in Hamburg (FLASH) at a wavelength of 8.0 nm is presented. Double pinhole diffraction patterns of single femtosecond pulses focused to a size of about 10 microns by 10 microns were measured. A transverse coherence length of 6.2 microns in the horizontal and 8.7 microns in the vertical direction was determined from the most coherent pulses. Using a split and delay unit the coherence time of the pulses produced in the same operation conditions of FLASH was measured to be 1.75 fs. From our experiment we estimated the degeneracy parameter of the FLASH beam to be on the order of $10^{10}$ to $10^{11}$, which exceeds the values of this parameter at any other source in the same energy range by many orders of magnitude.

  15. Analysis of Coherence Properties of 3-rd Generation Synchrotron Sources and Free-Electron Lasers

    CERN Document Server

    Vartanyants, I A

    2009-01-01

    A general theoretical approach based on the results of statistical optics is used for the analysis of the transverse coherence properties of 3-rd generation synchrotron sources and x-ray free-electron lasers (XFEL). Correlation properties of the wavefields are calculated at different distances from an equivalent Gaussian Schell-model source. This model is used to describe coherence properties of the five meter undulator source at the synchrotron storage ring PETRA III. In the case of XFEL sources the decomposition of the statistical fields into a sum of independently propagating transverse modes is used for the analysis of the coherence properties of these new sources. A detailed calculation is performed for the parameters of the SASE1 undulator at the European XFEL. It is demonstrated that only a few modes contribute significantly to the total radiation field of that source.

  16. Diffraction data of core-shell nanoparticles from an X-ray free electron laser.

    Science.gov (United States)

    Li, Xuanxuan; Chiu, Chun-Ya; Wang, Hsiang-Ju; Kassemeyer, Stephan; Botha, Sabine; Shoeman, Robert L; Lawrence, Robert M; Kupitz, Christopher; Kirian, Richard; James, Daniel; Wang, Dingjie; Nelson, Garrett; Messerschmidt, Marc; Boutet, Sébastien; Williams, Garth J; Hartmann, Elisabeth; Jafarpour, Aliakbar; Foucar, Lutz M; Barty, Anton; Chapman, Henry; Liang, Mengning; Menzel, Andreas; Wang, Fenglin; Basu, Shibom; Fromme, Raimund; Doak, R Bruce; Fromme, Petra; Weierstall, Uwe; Huang, Michael H; Spence, John C H; Schlichting, Ilme; Hogue, Brenda G; Liu, Haiguang

    2017-04-11

    X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Scattering patterns resulting from single particles were selected and compiled into a dataset which can be valuable for algorithm developments in single particle scattering research.

  17. Cluster sources for the low density matter beamline at the FERMI free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Katzy, Raphael; Lyamayev, Viktor; Mudrich, Marcel; Stienkemeier, Frank [Universitaet Freiburg, Physikalisches Institut, D-79104 Freiburg im Breisgau (Germany)

    2012-07-01

    Applying high gain harmonic generation process (HGHG) the new FERMI free electron laser in Trieste provides intense XUV pulses of high brilliance with tunable wavelength and excellent confinement in time. The LDM endstation has been designed to combine the FERMI XUV radiation with molecular beam experiments. In several exchangeable beam sources, atomic, molecular and cluster beams are generated and can be doped by the pick-up technique in oven cells or in a laser ablation unit. Detailed information about the interaction with the FEL light is gathered by combined VMI, TOF and X-ray imaging detectors. Design and characterization of two sources are presented: A versatile high temperature high pressure pulsed source is utilized for generation of atomic, molecular and cluster beams of various materials in a gas expansion or applying the seeded beams technique. A pulsed cryogenic source gives the opportunity to use helium droplets with their unique cold, superfluid properties.

  18. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    CERN Document Server

    Karbstein, Felix

    2016-01-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at a x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experim...

  19. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    Science.gov (United States)

    Karbstein, Felix; Sundqvist, Chantal

    2016-07-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article, we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at an x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experiment.

  20. Generation of high harmonic free electron laser with phase-merging effect

    Science.gov (United States)

    Li, Heting; Jia, Qika; Zhao, Zhouyu

    2017-03-01

    An easy-to-implement scheme is proposed to produce the longitudinal electron bunch density modulation with phase-merging phenomenon. In this scheme an electron bunch is firstly transversely dispersed in a modified dogleg to generate the exact dependence of electron energy on the transverse position, then it is modulated in a normal modulator. After travelling through a modified chicane with specially designed transfer matrix elements, the density modulation with phase-merging effect is generated which contains high harmonic components of the seed laser. We present theoretical analysis and numerical simulations for seeded soft x-ray free-electron laser. The results demonstrate that this technique can significantly enhance the frequency up-conversion efficiency and allow a seeded FEL operating at very high harmonics.

  1. An analysis on optimization of undulator in self-seeding free electron laser

    CERN Document Server

    Qika, Jia

    2013-01-01

    A simple analysis is given for optimum length of undulator in self-seeding free electron laser (FEL). The obtained relations show the correlation between the undulator length and the system parameters. The power required for the seeding in the second part undulator and overall efficiency to monochromatizating the seeding settle on the length of the first part undulator; the magnitude of seeding power dominates the length of the second part undulator; the whole length of the undulators in self-seeding FEL is determined by the overall efficiency to get coherent seed, it is about half as long again as that of SASE, not including the dispersion section. The requirement of the dispersion section strength is also analyzed.

  2. The ion channel free-electron laser with varying betatron amplitude

    Science.gov (United States)

    Ersfeld, B.; Bonifacio, R.; Chen, S.; Islam, M. R.; Smorenburg, P. W.; Jaroszynski, D. A.

    2014-09-01

    The ion-channel laser (ICL) is an ultra-compact version of the free-electron laser (FEL), with the undulator replaced by an ion channel. Previous studies of the ICL assumed transverse momentum amplitudes which were unrealistically small for experiments. Here we show that this restriction can be removed by correctly taking into account the dependence of the resonance between oscillations and emitted field on the betatron amplitude, which must be treated as variable. The ICL model with this essential addition is described using the well-known formalism for the FEL. Analysis of the resulting scaled equations shows a realistic prospect of building a compact ICL source for fundamental wavelengths down to UV, and harmonics potentially extending to x-rays. The gain parameter ρ can attain values as high as 0.03, which permits driving an ICL with electron bunches with realistic emittance.

  3. The Segmented Beamformer for Electromagnetic Waves of the Terahertz Free Electron Laser

    CERN Document Server

    Bogomolov, G D; Letunov, A A; Zavyalov, V V

    2015-01-01

    The quasi-optical segmented mirror for a formation of the target irradiation field was manufactured and investigated. It was designed for the high power THz beam of the free electron laser (FEL) using as a target a dust particle cloud, simulating cosmic dust. Numerical calculation of the beam shape and its low power laboratory measurements was made in the spectral region 1 - 3 THz of the first phase of the Novosibirsk FEL construction. The theoretical calculations of the diffraction effects reveal a speckle structure of a target spot, which was confirmed by the laboratory experiment. The beamformer technology was adapted for manufacturing and such device could be widely used for a concentration of powerful terahertz radiation.

  4. Design, construction and characterization of the compact ultrafast terahertz free-electron laser undulator

    Indian Academy of Sciences (India)

    B Biswas; V Kumar; S Chouksey; S Krishnagopal

    2008-12-01

    A compact ultrafast terahertz (CUTE) free-electron laser (FEL) is being developed at the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The undulator required for the CUTE-FEL has recently been developed. We have designed, built and characterized a variable gap, 5 cm period, 2.5 m long pure permanent magnet undulator in two identical segments. The tolerable error in the magnetic field was 1% in rms, and we have measured it to be 0.7%. The obtained rms phase shake is around 2°. To ensure that the trajectories do not have an exit error in position or angle, corrector coils have been designed. Shimming coils have been applied for both the undulator segments to reduce the amplitude of the betatron oscillations in the vertical trajectory. Details of novel corrector coils and soft iron shims are given and their performance is discussed.

  5. Time-resolved electron spectrum diagnostics for a free-electron laser

    Science.gov (United States)

    Gillespie, W. A.; MacLeod, A. M.; Martin, P. F.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1996-03-01

    Time-resolved electron-beam diagnostics have been developed for use with free-electron lasers (FELs) and associated electron sources, based on the techniques of secondary electron emission and optical transition radiation (OTR). The 32-channel OTR detector forms part of a high-resolution (0.18%) electron spectrometer with a time resolution of 50 ns. Variable-magnification optics allow the spectrometer to view single-macropulse spectra with widths in the range of 0.2%-7%; wider spectra are taken with several momentum settings. Design criteria for the spectrometer are presented, and experience of operating with the diagnostics over a range of FEL physics experiments is summarized. The spectrometer is used, in conjunction with optical diagnostics, in studies at FELIX of efficiency enhancement, pulse chirping, and stepped-undulator operation.

  6. Strong coupling operation of a free-electron-laser amplifier with an axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rullier, J.L.; Devin, A.; Gardelle, J.; Labrouche, J.; Le Taillandier, P. [Commissariat a lEnergie Atomique, Boite Postale 2, 33114 Le Barp (France); Donohue, J.T. [Centre dEtudes Nucleaires de Bordeaux-Gradignan, Boite Postale 120, 33175 Gradignan (France)

    1996-03-01

    We present the results of a free-electron-laser (FEL) experiment at 35 GHz, using a strongly relativistic electron beam ({ital T}=1.75 MeV). The electron pulse length is 30 ns full width at half maximum with a peak current of 400 A. The FEL is designed to operate in the high-gain Compton regime, with a negative coupling parameter ({Phi}{lt}0) leading to a strong growth rate. More than 50 MW of rf power in the TE{sub 1}{sub 1} mode (43 dB gain) has been obtained with good reproducibility. The experimental results are in good agreement with predictions made using the three-dimensional stationary simulation code solitude. {copyright} {ital 1996 The American Physical Society.}

  7. Thomson scattering from near-solid density plasmas using soft x-ray free electron lasers

    CERN Document Server

    Höll, A

    2006-01-01

    We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

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

    Science.gov (United States)

    Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu

    2010-06-01

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

  9. Spectrometer for X-ray emission experiments at FERMI free-electron-laser

    Energy Technology Data Exchange (ETDEWEB)

    Poletto, L., E-mail: poletto@dei.unipd.it; Frassetto, F.; Miotti, P. [CNR - Institute of Photonics and Nanotechnologies (CNR-IFN), via Trasea 7, I-35131 Padova (Italy); Di Cicco, A.; Iesari, F. [Physics Division, School of Science and Technology, Università di Camerino, I-62032 Camerino (Italy); Finetti, P. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); Grazioli, C. [Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy); CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Kivimäki, A. [CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Stagira, S. [Politecnico di Milano – Department of Physics, I-20133 Milano (Italy); Coreno, M. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); CNR – Istituto di Struttura della Materia (CNR-ISM), UOS Basovizza, I-34149 Trieste (Italy)

    2014-10-15

    A portable and compact photon spectrometer to be used for photon in-photon out experiments, in particular x-ray emission spectroscopy, is presented. The instrument operates in the 25–800 eV energy range to cover the full emissions of the FEL1 and FEL2 stages of FERMI. The optical design consists of two interchangeable spherical varied-lined-spaced gratings and a CCD detector. Different input sections can be accommodated, with/without an entrance slit and with/without an additional relay mirror, that allow to mount the spectrometer in different end-stations and at variable distances from the target area both at synchrotron and at free-electron-laser beamlines. The characterization on the Gas Phase beamline at ELETTRA Synchrotron (Italy) is presented.

  10. A CW normal-conductive RF gun for free electron laser and energy recovery linac applications

    Science.gov (United States)

    Baptiste, K.; Corlett, J.; Kwiatkowski, S.; Lidia, S.; Qiang, J.; Sannibale, F.; Sonnad, K.; Staples, J.; Virostek, S.; Wells, R.

    2009-02-01

    Currently proposed energy recovery linac and high average power free electron laser projects require electron beam sources that can generate up to ˜1 nC bunch charges with less than 1 mm mrad normalized emittance at high repetition rates (greater than ˜1 MHz). Proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose an approach for a gun fully based on mature RF and mechanical technology that greatly diminishes many of such complications. The concepts for such a source as well as the present RF and mechanical design are described. Simulations that demonstrate the beam quality preservation and transport capability of an injector scheme based on such a gun are also presented.

  11. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Krasniqi, F.; Rudenko, A. [Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany); Tschentscher, T. [European XFEL GmbH, Albert-Einstein-Ring 19, 22671 Hamburg (Germany); Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M. [HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg (Germany); Techert, S. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany)

    2012-11-01

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  12. Thomson scattering from near-solid density plasmas using soft x-ray free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Holl, A; Bornath, T; Cao, L; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gregori, G; Laarmann, T; Meiwes-Broer, K H; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Thiele, R; Tiggesbaumker, J; Toleikis, S; Truong, N X; Tschentscher, T; Uschmann, I; Zastrau, U

    2006-11-21

    We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

  13. High gain harmonic generation free electron lasers enhanced by pseudoenergy bands

    Science.gov (United States)

    Tanaka, Takashi; Kinjo, Ryota

    2017-08-01

    We propose a new scheme for high gain harmonic generation free electron lasers (HGHG FELs), which is seeded by a pair of intersecting laser beams to interact with an electron beam in a modulator undulator located in a dispersive section. The interference of the laser beams gives rise to a two-dimensional modulation in the energy-time phase space because of a strong correlation between the electron energy and the position in the direction of dispersion. This eventually forms pseudoenergy bands in the electron beam, which result in efficient harmonic generation in HGHG FELs in a similar manner to the well-known scheme using the echo effects. The advantage of the proposed scheme is that the beam quality is less deteriorated than in other existing schemes.

  14. Quantum effects with an x-ray free-electron laser.

    Science.gov (United States)

    Roberts, C D; Schmidt, S M; Vinnik, D V

    2002-10-07

    A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an x-ray free-electron laser (XFEL) facility to expose intrinsically quantum effects in the process of QED vacuum decay via spontaneous pair production. A 9 -TW-peak XFEL laser with photon energy of 8.3 keV could be sufficient to initiate particle accumulation and the consequent formation of a plasma of spontaneously produced pairs. The evolution of the particle number in the plasma will exhibit non-Markovian aspects of the strong-field pair production process, and the plasma's internal currents will generate an electric field whose interference with that of the laser leads to plasma oscillations.

  15. Bound-Free Electron-Positron Pair Production in Relativistic Heavy-Ion Collisions

    CERN Document Server

    Sengul, M Y; Fritzsche, S

    2009-01-01

    The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Colliders (LHC). In the framework of perturbation theory, we applied Monte-Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the elec- trons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au + Au at 100 GeV/nucleon and Pb + Pb at 3400 GeV/nucleon.

  16. A compact terahertz free-electron laser with two gratings driven by two electron-beams

    Science.gov (United States)

    Liu, Weihao; Lu, Yalin; Wang, Lin; Jia, Qika

    2017-02-01

    We proposed and investigated a novel terahertz free-electron laser, which is based on two gratings driven by two electron-beams. Two gratings are symmetrically arranged to form an open-cavity. Two electron-beams generate special Smith-Purcell radiations, respectively, from two gratings. When radiation interferes constructively, operation modes of the open-cavity are excited and then amplified by beam-wave interactions. By means of particle-in-cell simulations, we have shown that, with compact equipments and available electron-beams, this scheme can generate radiation with power and efficiency being higher than those of majority radiation sources in the vicinity region of 1 THz. It can promisingly be developed as a high-power, high-efficiency, and compact terahertz source for practice.

  17. Phase jump method for efficiency enhancement in free-electron lasers

    Directory of Open Access Journals (Sweden)

    Alan Mak

    2017-06-01

    Full Text Available The efficiency of a free-electron laser can be enhanced by the phase jump method. The method utilizes the phase-shifting chicanes in the drift sections between the undulator segments. By applying appropriate phase jumps, the microbunched electron beam can decelerate and radiate coherently beyond the initial saturation, enabling further energy transfer to the optical beam. This article presents a new physics model for the phase jump method, and supports it with numerical simulations. Based on the electron dynamics in the longitudinal phase space, the model describes the energy extraction mechanism, and addresses the selection criteria for the phase jump magnitude. While the ponderomotive bucket is stationary, energy can be extracted from electrons outside the bucket. With the aid of the new model, a comparison is made between the phase jump method and undulator tapering. The model also explores the potential of the phase jump method to suppress the growth of synchrotron sidebands in the optical spectrum.

  18. Obtaining attosecond x-ray pulses using a self-amplified spontaneous emission free electron laser

    Directory of Open Access Journals (Sweden)

    A. A. Zholents

    2005-05-01

    Full Text Available We describe a technique for the generation of a solitary attosecond x-ray pulse in a free-electron laser (FEL, via a process of self-amplified spontaneous emission. In this method, electrons experience an energy modulation upon interacting with laser pulses having a duration of a few cycles within single-period wiggler magnets. Two consecutive modulation sections, followed by compression in a dispersive section, are used to obtain a single, subfemtosecond spike in the electron peak current. This region of the electron beam experiences an enhanced growth rate for FEL amplification. After propagation through a long undulator, this current spike emits a ∼250   attosecond x-ray pulse whose intensity dominates the x-ray emission from the rest of the electron bunch.

  19. Performance of the x-ray free-electron laser oscillator with crystal cavity

    Directory of Open Access Journals (Sweden)

    R. R. Lindberg

    2011-01-01

    Full Text Available Simulations of the x-ray free-electron laser (FEL oscillator are presented that include the frequency-dependent Bragg crystal reflectivity and the transverse diffraction and focusing using the two-dimensional FEL code GINGER. A review of the physics of Bragg crystal reflectors and the x-ray FEL oscillator is made, followed by a discussion of its numerical implementation in GINGER. The simulation results for a two-crystal cavity and realistic FEL parameters indicate ∼10^{9} photons in a nearly Fourier-limited, ps pulse. Compressing the electron beam to 100 A and 100 fs results in comparable x-ray characteristics for relaxed beam emittance, energy spread, and/or undulator parameters, albeit in a larger radiation bandwidth. Finally, preliminary simulation results indicate that the four-crystal FEL cavity can be tuned in energy over a range of a few percent.

  20. Phase matching strategy for the undulator system in the European X-ray Free Electron Laser

    Science.gov (United States)

    Li, Yuhui; Pflueger, Joachim

    2017-02-01

    The undulator system in the European X-ray Free Electron Laser is mainly comprised of 5-m long undulator segments and 1.1 m long intersections in between. The longitudinal component of the electrons' velocity is reduced when traveling inside an undulator due to the wiggle motion. Therefore the optical phase is detuned. The detune effect is also from the undulator fringe field where electron longitudinal speed also deviates from the oscillation condition. The total detune effect is compensated by a magnetic device called phase shifter, which is correspondingly set for a specific undulator gap. In this paper we investigate the homogeneity of the fringe field from different undulators. Different phase matching criteria are studied. The field fitting technique for the phase matching in high accuracy is demonstrated in detail. The impact by air coil is also studied. Eventually the matching test by spontaneous radiation simulation is made. A test method for high sensitivity to matching error is proposed.