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Sample records for fermi fel facility

  1. FERMI@Elettra FEL Design Technical Optimization Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, William; Penn, Gregory; Allaria, Enrico; De Ninno,Giovanni; Graves, William

    2006-07-31

    This is the final report of the FEL Design Group for the Technical Optimization Study for the FERMI{at}ELETTRA project. The FERMI{at}ELETTRA project is based on the principle of harmonic upshifting of an initial ''seed'' signal in a single pass, FEL amplifier employing multiple undulators. There are a number of FEL physics principles which underlie this approach to obtaining short wavelength output: (1) the energy modulation of the electron beam via the resonant interaction with an external laser seed (2) the use of a chromatic dispersive section to then develop a strong density modulation with large harmonic overtones (3) the production of coherent radiation by the microbunched beam in a downstream radiator. Within the context of the FERMI project, we discuss each of these elements in turn.

  2. The Shanghai FEL User Facility

    Institute of Scientific and Technical Information of China (English)

    ZhaoXiao-Feng; LuoYing-Xiong; 等

    1998-01-01

    The shanghai FEL User Facility(SFEL) for interdisciplinary studies is based on a rf linear accelerator.the prime goal of SEFL is provide a brodly tunable laser beam from near=IR to far-IR with tens of MW at peak power,A linear accelerator will operate in three modes:-3 MeV moed,20-30MeV mode and 40-50MeV mode.In 20-30 MeV mode,the accelerator consists of a ns grid gun driven at 476MHzm,a 476MHz subharmonic buncher,a 2856 MHz T-W type of buncher with high field gradients,and a SLAC type linac.

  3. Optimization and Modeling of the Accelerator for the FERMI @ Elettra FEL

    CERN Document Server

    Di Mitri, S; Emma, P; Huang, Z; Wang, D; Wu, J; Zholents, A; Craievich, P

    2005-01-01

    Design studies are in progress to use the existing FERMI@Elettra linear accelerator for a seeded harmonic cascade FEL facility [1]. This accelerator will be upgraded to 1.2 GeV and equipped with a low-emittance RF photocathode gun, laser heater, two bunch compressors, and beam delivery system. We present an optimization study for all the components following the gun, with the aim of achieving high peak current, low energy spread and low emittance electron beam necessary for the FEL. Various operational scenarios are discussed. Results of accelerator simulations including effects of space charge, coherent synchrotron radiation, and wakefields are reported.

  4. Optimization Studies of the FERMI at ELETTRA FEL Design

    CERN Document Server

    De Ninno, G

    2005-01-01

    The FERMI at ELETTRA project at Sincotrone Trieste involves two FEL's, each based upon the principle of a seeded harmonic cascade and using the existing ELETTRA injection linac at 1.2 GeV beam energy. Scheduled to be completed in 2008, FEL-1 will operate in the 40-100 nm wavelength range and will involve one stage of harmonic up-conversion. The second phase, FEL-2, will begin operation two years later in the 10-40 nm wavelength range and will involve two cascade stages. FEL design assumes wavelength tunability over the full wavelength range and polarization tunability of the output radiation including helical polarization. The design considers focusing properties and segmentation of realizable undulators and available input seed lasers. We discuss how the interplay between various limitations and self-consistent accelerator simulations [1,2] have led to our current design. We present results of simulations using GENESIS and GINGER simulation codes including studies of various shot-to-shot fluctuations and und...

  5. FERMI @ Elettra -- A Seeded Harmonic Cascade FEL for EUV and SoftX-rays

    Energy Technology Data Exchange (ETDEWEB)

    Bocchetta, C.; Bulfone, D.; Craievich, P.; Danailov, M.B.; D' Auria,G.; DeNinno, G.; Di Mitri, S.; Diviacco, B.; Ferianis, M.; Gomezel, A.; Iazzourene, F.; Karantzoulis, E.; Parmigiani, F.; Penco, G.; Trovo, M.; Corlett, J.; Fawley, W.; Lidia, S.; Penn, G.; Ratti, A.; Staples, J.; Wilcox, R.; Zholents, A.; Graves, W.; Ilday, F.O.; Kaertner,F.; Wang, D.; Zwart, T.; Cornacchia, M.; Emma, P.; Huang, Z.; Wu, J.

    2005-09-01

    We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy, within the next five years. The project will be the first user facility based on seeded harmonic cascade FELs, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from {approx}100 nm to {approx}10nm, with pulse duration from 40 fs to {approx} 1 ps, peak power GW, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate >40 nm, and a two stage cascade operating from {approx}40 nm to {approx}10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing system providing synchronization of rf signals, lasers, and x-ray pulses. Major systems and overall facility layout are described, and key performance parameters summarized.

  6. FERMI@Elettra: A Seeded Harmonic Cascade FEL for EUV and Soft X-Rays

    Energy Technology Data Exchange (ETDEWEB)

    Bocchetta, C.J.; Bulfone, D.; Craievich, P.; Danailov, M.B.; D' Auria, G.; De Ninno, G.; Di Mitri, S.; Diviacco, B.; Ferianis, M.; Gomezel, A.; Iazzourene, F.; Karantzoulis, E.; Parmigiani, F.; Penco, G.; Trovo, M.; /Sincrotrone Trieste; Corlett, J.; Fawley, W.; Lidia, S.; Penn, G.; Ratti, A.; Staples, J.; /LBL, Berkeley /MIT /SLAC

    2005-12-14

    We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy, within the next five years. The project will be the first user facility based on seeded harmonic cascade FEL's, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from {approx}100 nm to {approx}10 nm, with pulse duration from 40 fs to {approx} 1ps, peak power {approx}GW, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate > 40 nm, and a two-stage cascade operating from {approx}40 nm to {approx}10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing system providing synchronization of rf signals, lasers, and x-ray pulses. Major systems and overall facility layout are described, and key performance parameters summarized.

  7. FERMI @ Elettra A Seeded Harmonic Cascade FEL for EUV and Soft X-Rays

    CERN Document Server

    Bocchetta, C J; Craievich, P; D'Auria, G; Danailov, M B; De Ninno, G; Di Mitri, S; Diviacco, B; Ferianis, M; Gomezel, A; Iazzourene, F; Karantzoulis, E; Penco, G; Trovò, M

    2005-01-01

    We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy. The project will be the first user facility based on seeded harmonic cascade FELs, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from ~100 nm to ~10 nm, with pulse duration from 40 fs to ~ 1ps, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate > 40 nm, and a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing sys...

  8. Renewal of KU-FEL Facility

    CERN Document Server

    Kii, Toshiteru; Masuda, Kai; Murakami, Shio; Ohgaki, Hideaki; Yamazaki, Tetsuo; Yoshikawa, Kiyoshi; Zen, Heishun

    2004-01-01

    Users demands to a high power tunable IR laser are increasing in Japan in energy-related science, such as basic study of high-efficiency solar cells, generation of new energy source of alcohol and/or H2 from polluted gas, and separation of DNA and/or RNA. To satisfy these demands, we decided to renew our FEL facility more user friendly and to operate more flexibly. Construction and fundamental studies on the KU-FEL have been carried out at a building of Institute of Chemical Research where few other accelerators are operating. Therefore, available machine time for our experiments is quite limited. We are now modifying the room by adding concrete walls of 2-m thickness and some space for users will be available. The present FEL system will be moved to the room A photocathode RF-gun system will be nearly added to the system and the present thermionic RF-gun will be used ternatively according to the demands of users. The photocathode material will be Cs2Te. The room with the shielding will be completed in June, ...

  9. The BESSY Soft X-Ray FEL User Facility

    CERN Document Server

    Kraemer, Dieter

    2005-01-01

    The user requests for an optimized 2nd generation FEL facility in the VUV to soft X-ray range demand for ultra short photon pulses (t = 20 fs) at a peak power of several GW. A high shot to shot reproducibility of the pulse shape and pulse power allowing for fs-synchronization for pump-probe experiments is feasible in a seeded FEL approach. Free selectable photon polarization and wavelength tuning is essential for any 2nd generation FEL source like the proposed BESSY-Soft X-ray FEL user facility. Freely selectable pulse repetition rates and freely selectable pulse patterns, including fast switching to different parallel operating FEL-Lines are necessary ingredients, feasible with a suitable injector in combination with a CW-superconducting linac. The status of the BESSY HGHG-FEL project will be reviewed.

  10. Optical properties of infrared FELs from the FELI Facility II

    Energy Technology Data Exchange (ETDEWEB)

    Saeki, K.; Okuma, S.; Oshita, E. [Free Electron Laser Institute, Osaka (Japan)] [and others

    1995-12-31

    The FELI Facility II has succeeded in infrared FEL oscillation at 1.91 {mu} m using a 68-MeV, 40-A electron beam from the FELI S-band linac in February 27, 1995. The FELI Facility II is composed of a 3-m vertical type undulator ({lambda}u=3.8cm, N=78, Km a x=1.4, gap length {ge}20mm) and a 6.72-m optical cavity. It can cover the wavelength range of 1-5{mu}m. The FELs can be delivered from the optical cavity to the diagnostics room through a 40-m evacuated optical pipeline. Wavelength and cavity length dependences of optical properties such as peak power, average power, spectrum width, FEL macropulse, FEL transverse profile are reported.

  11. Wavefront sensor based diagnostic of FERMI FEL photon beam (Conference Presentation)

    Science.gov (United States)

    Raimondi, Lorenzo; Mahne, Nicola; Manfredda, Michele; Svetina, Cristian; Cocco, Daniele; Capotondi, Flavio; Pedersoli, Emanuele; Kiskinova, Maya; Zangrando, Marco

    2016-09-01

    FERMI is the first seeded EUV-SXR free electron laser (FEL) user facility, and it is operated at Elettra Sincrotrone Trieste. Two of the four already operating beamlines, namely LDM (Low Density Matter) and DiProI (Diffraction and Projection Imaging), use a Kirkpatrick-Baez (K-B) active X-ray optics system for focusing the FEL pulses onto the target under investigation. A wafefront sensor is used as diagnostic for the characterization of the focused spot and for the optimization of the parameters of these active optical systems as well. The aim of this work is, first, to describe in detail the optimization procedure using the wavefront sensor through the minimization of the Zernike coefficients, and second, report on the final results obtained on the K-B optical system at the DiProI endstation. The wavefront sensor, mounted out of focus behind the DiProI chamber, allows to compute the intensity distribution of the FEL beam, typically a mix between several modes resulting in a "noisy hyper-Gaussian" intensity profile, and the wavefront residual from ideal propagation shape and after tilt correction. Combining these two measures we can obtain the electric field of the wave out of focus. Propagating back the electric field we reconstruct the focal spot in far field approximation. In this way the sensor works as a diagnostic reconstructing the focal spot. On the other hand, after modelling the electric field with a Zernike polynomial it is easy and fast to optimize the mirror bending and the optical system angles by minimizing the aberrations, quantified in terms of Zernike coefficients. Since each coefficient corresponds to a single parameter, they can be minimized one at the time. Online wavefront measurements have made possible the optimization of the bending acting on the mirror curvature, and of the (pitch and roll) angle positions of the K-B system. From the wavefront measurements we have inferred a focal spot for DiProI of 5.5 μm x 6.2 μm at 32 nm wavelength

  12. A proposed visible FEL Facility at Boeing

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, D.H.; Adamski, J.L.; Hayward, T.D. [Boeing Defense & Space Group, Seattle, WA (United States)] [and others

    1995-12-31

    A 1-kW average power, visible wavelength FEL is described, based on a 120-MeV, 0.1. A macropulse average current linac operating at a duty factor of 0. 6% and having average beam power of 70 kW. The accelerator will employ a demonstrated photoinjector, 18-MeV, 433-MHz linac as an injector, followed by a 1300-MHz longitudinal phase space {open_quotes} linearizer,{close_quotes} a magnetic buncher chicane, and seven 1300-MHz, pulsed traveling wave linac sections. The magnets used to transport the beam from the linac to the FEL centerline, the 5-m THUNDER wiggler, and the optical resonator will be reclaimed from previous FEL demonstration experiments. We expect to attain pulse lengths of 7 ps for 3.5 nC, with minimal distortion of the pulse profile and normalized rms emittance of 7.5 {+-} 2.5 {pi} mm-mr. FELEX projects a laser conversion efficiency of 4.3 %, yielding average output of 3 kW.

  13. The FERMI @ Elettra Technical Optimization Study: General Layoutand Parameters and Physics Studies of Longitudinal Space Charge, theSpreader, the Injector, and Preliminary FEL Performance

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, John; Corlett, John; Doolittle, Larry; Fawley, William; Lidia, Steven; Penn, Gregory; Ratti, Alex; Staples, John; Wilcox,Russell; Wurtele, Jonathan; Zholents, Alexander

    2005-09-01

    The FERMI {at} Elettra facility will make use of the existing GeV linac at Sincrotrone Elettra, which will become available for dedicated FEL applications following the completion of construction of a new injector booster complex for the storage ring. With a new rf photocathode injector, and some additional accelerating sections, this linac will be capable of providing high brightness bunches at 1.2 GeV and up to 50 Hz repetition rates.

  14. Experimental setups for FEL-based four-wave mixing experiments at FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs–nm time–length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  15. Experimental setups for FEL-based four-wave mixing experiments at FERMI.

    Science.gov (United States)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs-nm time-length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  16. Experimental setups for FEL-based four-wave mixing experiments at FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs–nm time–length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  17. EXPERIENCE AND PLANS OF THE JLAB FEL FACILITY AS A USER FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Michelle D. Shinn

    2007-08-26

    Jefferson Lab's IR Upgrade FEL building was planned from the beginning to be a user facility, and includes an associated 600 m2 area containing seven laboratories. The high average power capability (multikilowatt-level) in the near-infrared (1-3 microns), and many hundreds of watts at longer wavelengths, along with an ultrafast (~ 1 ps) high PRF (10's MHz) temporal structure makes this laser a unique source for both applied and basic research. In addition to the FEL, we have a dedicated laboratory capable of delivering high power (many tens of watts) of broadband THz light. After commissioning the IR Upgrade, we once again began delivering beam to users in 2005. In this presentation, I will give an overview of the FEL facility and its current performance, lessons learned over the last two years, and a synopsis of current and future experiments.

  18. The PixFEL project: Progress towards a fine pitch X-ray imaging camera for next generation FEL facilities

    Science.gov (United States)

    Rizzo, G.; Batignani, G.; Benkechkache, M. A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Dalla Betta, G.-F.; Fabris, L.; Forti, F.; Grassi, M.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Mendicino, R.; Morsani, F.; Paladino, A.; Pancheri, L.; Paoloni, E.; Ratti, L.; Re, V.; Traversi, G.; Vacchi, C.; Verzellesi, G.; Xu, H.

    2016-07-01

    The INFN PixFEL project is developing the fundamental building blocks for a large area X-ray imaging camera to be deployed at next generation free electron laser (FEL) facilities with unprecedented intensity. Improvement in performance beyond the state of art in imaging instrumentation will be explored adopting advanced technologies like active edge sensors, a 65 nm node CMOS process and vertical integration. These are the key ingredients of the PixFEL project to realize a seamless large area focal plane instrument composed by a matrix of multilayer four-side buttable tiles. In order to minimize the dead area and reduce ambiguities in image reconstruction, a fine pitch active edge thick sensor is being optimized to cope with very high intensity photon flux, up to 104 photons per pixel, in the range from 1 to 10 keV. A low noise analog front-end channel with this wide dynamic range and a novel dynamic compression feature, together with a low power 10 bit analog to digital conversion up to 5 MHz, has been realized in a 110 μm pitch with a 65 nm CMOS process. Vertical interconnection of two CMOS tiers will be also explored in the future to build a four-side buttable readout chip with high density memories. In the long run the objective of the PixFEL project is to build a flexible X-ray imaging camera for operation both in burst mode, like at the European X-FEL, or in continuous mode with the high frame rates anticipated for future FEL facilities.

  19. The PixFEL project: Progress towards a fine pitch X-ray imaging camera for next generation FEL facilities

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, G., E-mail: giuliana.rizzo@pi.infn.it [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Batignani, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Benkechkache, M.A. [Università di Trento, Dipartimento di Ingegneria Industriale, I-38123 Trento (Italy); University Constantine 1, Department of Electronics in the Science and Technology Faculty, I-25017, Constantine (Algeria); Bettarini, S.; Casarosa, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Comotti, D. [Università di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Dalla Betta, G.-F. [Università di Trento, Dipartimento di Ingegneria Industriale, I-38123 Trento (Italy); TIFPA INFN, I-38123 Trento (Italy); Fabris, L. [INFN Sezione di Pavia, I-27100 Pavia (Italy); Università di Bergamo, Dipartimento di Ingegneria e Scienze Applicate, I-24044 Dalmine (Italy); Forti, F. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Grassi, M.; Lodola, L.; Malcovati, P. [Università di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Manghisoni, M. [INFN Sezione di Pavia, I-27100 Pavia (Italy); Università di Bergamo, Dipartimento di Ingegneria e Scienze Applicate, I-24044 Dalmine (Italy); and others

    2016-07-11

    The INFN PixFEL project is developing the fundamental building blocks for a large area X-ray imaging camera to be deployed at next generation free electron laser (FEL) facilities with unprecedented intensity. Improvement in performance beyond the state of art in imaging instrumentation will be explored adopting advanced technologies like active edge sensors, a 65 nm node CMOS process and vertical integration. These are the key ingredients of the PixFEL project to realize a seamless large area focal plane instrument composed by a matrix of multilayer four-side buttable tiles. In order to minimize the dead area and reduce ambiguities in image reconstruction, a fine pitch active edge thick sensor is being optimized to cope with very high intensity photon flux, up to 10{sup 4} photons per pixel, in the range from 1 to 10 keV. A low noise analog front-end channel with this wide dynamic range and a novel dynamic compression feature, together with a low power 10 bit analog to digital conversion up to 5 MHz, has been realized in a 110 μm pitch with a 65 nm CMOS process. Vertical interconnection of two CMOS tiers will be also explored in the future to build a four-side buttable readout chip with high density memories. In the long run the objective of the PixFEL project is to build a flexible X-ray imaging camera for operation both in burst mode, like at the European X-FEL, or in continuous mode with the high frame rates anticipated for future FEL facilities.

  20. 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.

  1. The Upgrade of the DUV-FEL Facility at the BNL

    CERN Document Server

    Wang, Xijie; Murphy, James; Rakowsky, George; Rose, James; Sheehy, Brian; Shen, Yuzhen; Skaritka, John; Wu, Zilu; Yu Li Hua

    2004-01-01

    The DUV-FEL at BNL, is the world's only facility dedicated to laser-seeded FEL R&D and its applications. The HGHG at the DUV-FEL reached saturation at 266 nm with 800 nm seeding [1] in 2002. Since then, the first chemical science experiment ? ion pair imaging, was successfully completed [2].The DUV-FEL linac is being upgraded from 200 to 300 MeV to enable the HGHG FEL to produce 100 μJ pulses of 100 nm light. This will establish the DUV FEL as a premier user facility for XUV radiation. The upgraded facility will also enable several critical R&Ds for a future X-ray FEL based on HGHG, such as cascaded HGHG and higher harmonic HGHG (n>5). The upgraded HGHG will operate at the 4th harmonic with the seed laser at 400nm. The increase of the electron beam energy will be accomplished by installing a 5th linac cavity and two 45 MW klystrons. New modulator and dispersion sections vacuum chambers will be manufactured to accommodate new matching optics and 8th harmonic HGHG. The status of the DUV-FEL upgra...

  2. Plasma switch as a temporal overlap tool for pump-probe experiments at FEL facilities

    Science.gov (United States)

    Harmand, M.; Murphy, C. D.; Brown, C. R. D.; Cammarata, M.; Döppner, T.; Düsterer, S.; Fritz, D.; Förster, E.; Galtier, E.; Gaudin, J.; Glenzer, S. H.; Göde, S.; Gregori, G.; Hilbert, V.; Hochhaus, D.; Laarmann, T.; Lee, H. J.; Lemke, H.; Meiwes-Broer, K.-H.; Moinard, A.; Neumayer, P.; Przystawik, A.; Redlin, H.; Schulz, M.; Skruszewicz, S.; Tavella, F.; Tschentscher, T.; White, T.; Zastrau, U.; Toleikis, S.

    2012-08-01

    We have developed an easy-to-use and reliable timing tool to determine the arrival time of an optical laser and a free electron laser (FEL) pulses within the jitter limitation. This timing tool can be used from XUV to X-rays and exploits high FELs intensities. It uses a shadowgraph technique where we optically (at 800 nm) image a plasma created by an intense XUV or X-ray FEL pulse on a transparent sample (glass slide) directly placed at the pump - probe sample position. It is based on the physical principle that the optical properties of the material are drastically changed when its free electron density reaches the critical density. At this point the excited glass sample becomes opaque to the optical laser pulse. The ultra-short and intense XUV or X-ray FEL pulse ensures that a critical electron density can be reached via photoionization and subsequent collisional ionization within the XUV or X-ray FEL pulse duration or even faster. This technique allows to determine the relative arrival time between the optical laser and the FEL pulses in only few single shots with an accuracy mainly limited by the optical laser pulse duration and the jitter between the FEL and the optical laser. Considering the major interest in pump-probe experiments at FEL facilities in general, such a femtosecond resolution timing tool is of utmost importance.

  3. Present Status and Results from the KAERI Compact THz FEL Facility

    CERN Document Server

    Jeong, Y U; Lee, B C; Park, S H

    2005-01-01

    We have developed a laboratory-scale users facility with a compact terahertz (THz) free electron laser (FEL). The FEL operates in the wavelength range of 100-1200 μm, which corresponds to 0.3-3 THz. The peak power of the FEL micropulse having 30 ps pulse duration is 1 kW and the pulse energy of the 3-μs-FEL-macropulse is approximately 0.3 mJ. The main application of the FEL is THz imaging for bio-medical researches. Transmitted THz imaging of various samples including bugs have been measured. The samples were scanned by a 2-dimensional stage at the focal point of the THz beam. The bugs were not dry because they were killed just before experiments. We could get the transmitted THz imaging of the bugs at 3 THz with the high power THz FEL. THz spectral characteristics of several materials have been studied by the FEL and a THz FTIR spectrometer. We will introduce recent results on the imaging and spectroscopy by the THz FEL.

  4. Mine-detection test facilities at TNO-FEL test location "Waalsdorp"

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.

    1998-01-01

    As part of the TNO-FEL Ultra-Wide-Band Ground-Penetrating-Radar (UWB-GPR) project, a test facility for controlled GPR experiments was planned. Construction of this sand-box test facility has recently been completed. At the same site another test facility, for evaluating various commercial of the

  5. Mine-detection test facilities at TNO-FEL test location "Waalsdorp"

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.

    1998-01-01

    As part of the TNO-FEL Ultra-Wide-Band Ground-Penetrating-Radar (UWB-GPR) project, a test facility for controlled GPR experiments was planned. Construction of this sand-box test facility has recently been completed. At the same site another test facility, for evaluating various commercial of the she

  6. The bunch compression system at the TESLA test facility FEL

    Science.gov (United States)

    Limberg, T.; Weise, H.; Molodozhentsev, A.; Petrov, V.

    1996-02-01

    A SASE-FEL [A.M. Kontradenko and E.L. Saldin, Particle Accelerators 10 (1980) 207; R. Bonifacio, C. Pellegrini and I.M. Narducci, Opt. Commun. 50 (1884) 373] requires extremely high peak currents which cannot be achieved by electron guns. The bunch length therefore has to be reduced along the accelerating linac, the bunch has to be compressed. In the TTF-FEL this is done with the help of bending magnet chicanes in three stages. We present the lay-out of the scheme as well as first beam dynamics calculations.

  7. 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.

  8. An FEL based high-intensity gamma source at the TESLA Test Facility at DESY

    CERN Document Server

    Pagani, C; Schneidmiller, E A; Yurkov, M V

    1999-01-01

    One possible extension of the FEL activity at DESY is connected with the installation of an additional FEL beamline providing tunable UV radiation with peak and average power of 220 GW and 7 kW, respectively. This report presents the feasibility study of a high-intensity, polarized, monochromatic gamma source at the TESLA Test Facility. Gamma quanta are produced in the process of Compton backscattering of the UV FEL radiation on 1 GeV electrons of the TTF accelerator. The ultimate intensity of the gamma source can reach a value up to 10 sup 1 sup 2 gamma quanta per second with a maximum energy of about 100 MeV. The energy resolution of the gamma source can be reduced down to a value of about 0.2%. Potential applications of the intense gamma source at the TESLA Test Facility are discussed as well.

  9. Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility

    Directory of Open Access Journals (Sweden)

    T. Schietinger

    2016-10-01

    Full Text Available The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and test bed for the development and realization of SwissFEL, the x-ray Free-Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including a transverse deflecting rf cavity. It delivered electron bunches of up to 200 pC charge and up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of an FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultralow-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics measurements performed during the operation of the test facility, including the results of the test of an in-vacuum undulator prototype generating radiation in the vacuum ultraviolet and optical range.

  10. Microfocusing of the FERMI@Elettra FEL beam with a K–B active optics system: Spot size predictions by application of the WISE code

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, L., E-mail: lorenzo.raimondi@elettra.trieste.it [Sincrotrone Trieste ScpA, S.S. 14 km 163.5 in Area Science Park, 34149 Trieste (Italy); Svetina, C.; Mahne, N. [Sincrotrone Trieste ScpA, S.S. 14 km 163.5 in Area Science Park, 34149 Trieste (Italy); Cocco, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS-19 Menlo Park, CA 94025 (United States); Abrami, A.; De Marco, M.; Fava, C.; Gerusina, S.; Gobessi, R.; Capotondi, F.; Pedersoli, E.; Kiskinova, M. [Sincrotrone Trieste ScpA, S.S. 14 km 163.5 in Area Science Park, 34149 Trieste (Italy); De Ninno, G. [Sincrotrone Trieste ScpA, S.S. 14 km 163.5 in Area Science Park, 34149 Trieste (Italy); University of Nova Gorica, Vipavska 13, Rozna Dolina, SI-5000 Nova Gorica (Slovenia); Zeitoun, P. [Laboratoire d' Optique Appliquée, CNRS-ENSTA-École Polytechnique, Chemin de la Humiére, 91761 Palaiseau (France); Dovillaire, G. [Imagine Optic, 18 Rue Charles de Gaulle, 91400 Orsay (France); Lambert, G. [Laboratoire d' Optique Appliquée, CNRS-ENSTA-École Polytechnique, Chemin de la Humiére, 91761 Palaiseau (France); Boutu, W.; Merdji, H.; Gonzalez, A.I. [Service des Photons, Atomes et Molécules, IRAMIS, CEA-Saclay, Btiment 522, 91191 Gif-sur-Yvette (France); Gauthier, D. [University of Nova Gorica, Vipavska 13, Rozna Dolina, SI-5000 Nova Gorica (Slovenia); and others

    2013-05-11

    FERMI@Elettra, the first seeded EUV-SXR free electron laser (FEL) facility located at Elettra Sincrotrone Trieste has been conceived to provide very short (10–100 fs) pulses with ultrahigh peak brightness and wavelengths from 100 nm to 4 nm. A section fully dedicated to the photon transport and analysis diagnostics, named PADReS, has already been installed and commissioned. Three of the beamlines, EIS-TIMEX, DiProI and LDM, installed after the PADReS section, are in advanced commissioning state and will accept the first users in December 2012. These beam lines employ active X-ray optics in order to focus the FEL beam as well as to perform a controlled beam-shaping at focus. Starting from mirror surface metrology characterization, it is difficult to predict the focal spot shape applying only methods based on geometrical optics such as the ray tracing. Within the geometrical optics approach one cannot take into account the diffraction effect from the optics edges, i.e. the aperture diffraction, and the impact of different surface spatial wavelengths to the spot size degradation. Both these effects are strongly dependent on the photon beam energy and mirror incident angles. We employed a method based on physical optics, which applies the Huygens–Fresnel principle to reflection (on which the WISE code is based). In this work we report the results of the first measurements of the focal spot in the DiProI beamline end-station and compare them to the predictions computed with Shadow code and WISE code, starting from the mirror surface profile characterization.

  11. Microfocusing of the FERMI@Elettra FEL beam with a K-B active optics system: Spot size predictions by application of the WISE code

    Science.gov (United States)

    Raimondi, L.; Svetina, C.; Mahne, N.; Cocco, D.; Abrami, A.; De Marco, M.; Fava, C.; Gerusina, S.; Gobessi, R.; Capotondi, F.; Pedersoli, E.; Kiskinova, M.; De Ninno, G.; Zeitoun, P.; Dovillaire, G.; Lambert, G.; Boutu, W.; Merdji, H.; Gonzalez, A. I.; Gauthier, D.; Zangrando, M.

    2013-05-01

    FERMI@Elettra, the first seeded EUV-SXR free electron laser (FEL) facility located at Elettra Sincrotrone Trieste has been conceived to provide very short (10-100 fs) pulses with ultrahigh peak brightness and wavelengths from 100 nm to 4 nm. A section fully dedicated to the photon transport and analysis diagnostics, named PADReS, has already been installed and commissioned. Three of the beamlines, EIS-TIMEX, DiProI and LDM, installed after the PADReS section, are in advanced commissioning state and will accept the first users in December 2012. These beam lines employ active X-ray optics in order to focus the FEL beam as well as to perform a controlled beam-shaping at focus. Starting from mirror surface metrology characterization, it is difficult to predict the focal spot shape applying only methods based on geometrical optics such as the ray tracing. Within the geometrical optics approach one cannot take into account the diffraction effect from the optics edges, i.e. the aperture diffraction, and the impact of different surface spatial wavelengths to the spot size degradation. Both these effects are strongly dependent on the photon beam energy and mirror incident angles. We employed a method based on physical optics, which applies the Huygens-Fresnel principle to reflection (on which the WISE code is based). In this work we report the results of the first measurements of the focal spot in the DiProI beamline end-station and compare them to the predictions computed with Shadow code and WISE code, starting from the mirror surface profile characterization.

  12. Commissioning experience and beam physics measurements at the SwissFEL Injector test Facility

    CERN Document Server

    Schietinger, T.; Aiba, M.; Arsov, V.; Bettoni, S.; Beutner, B.; Calvi, M.; Craievich, P.; Dehler, M.; Frei, F.; Ganter, R.; Hauri, C. P.; Ischebeck, R.; Ivanisenko, Y.; Janousch, M.; Kaiser, M.; Keil, B.; Löhl, F.; Orlandi, G. L.; Ozkan Loch, C.; Peier, P.; Prat, E.; Raguin, J.-Y.; Reiche, S.; Schilcher, T.; Wiegand, P.; Zimoch, E.; Anicic, D.; Armstrong, D.; Baldinger, M.; Baldinger, R.; Bertrand, A.; Bitterli, K.; Bopp, M.; Brands, H.; Braun, H. H.; Brönnimann, M.; Brunnenkant, I.; Chevtsov, P.; Chrin, J.; Citterio, A.; Csatari Divall, M.; Dach, M.; Dax, A.; Ditter, R.; Divall, E.; Falone, A.; Fitze, H.; Geiselhart, C.; Guetg, M. W.; Hämmerli, F.; Hauff, A.; Heiniger, M.; Higgs, C.; Hugentobler, W.; Hunziker, S.; Janser, G.; Kalantari, B.; Kalt, R.; Kim, Y.; Koprek, W.; Korhonen, T.; Krempaska, R.; Laznovsky, M.; Lehner, S.; Le Pimpec, F.; Lippuner, T.; Lutz, H.; Mair, S.; Marcellini, F.; Marinkovic, G.; Menzel, R.; Milas, N.; Pal, T.; Pollet, P.; Portmann, W.; Rezaeizadeh, A.; Ritt, S.; Rohrer, M.; Schär, M.; Schebacher, L.; Scherrer, St.; Schlott, V.; Schmidt, T.; Schulz, L.; Smit, B.; Stadler, M.; Steffen, Bernd; Stingelin, L.; Sturzenegger, W.; Treyer, D. M.; Trisorio, A.; Tron, W.; Vicario, C.; Zennaro, R.; Zimoch, D.

    2016-10-26

    The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and test bed for the development and realization of SwissFEL, the x-ray Free Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including atransverse deflecting rf cavity. It delivered electron bunchesof up to200 pC chargeand up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of a FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultralow-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics measureme...

  13. Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility

    CERN Document Server

    Schietinger, T; Aiba, M; Arsov, V; Bettoni, S; Beutner, B; Calvi, M; Craievich, P; Dehler, M; Frei, F; Ganter, R; Hauri, C P; Ischebeck, R; Ivanisenko, Y; Janousch, M; Kaiser, M; Keil, B; Löhl, F; Orlandi, G L; Loch, C Ozkan; Peier, P; Prat, E; Raguin, J -Y; Reiche, S; Schilcher, T; Wiegand, P; Zimoch, E; Anicic, D; Armstrong, D; Baldinger, M; Baldinger, R; Bertrand, A; Bitterli, K; Bopp, M; Brands, H; Braun, H H; Brönnimann, M; Brunnenkant, I; Chevtsov, P; Chrin, J; Citterio, A; Divall, M Csatari; Dach, M; Dax, A; Ditter, R; Divall, E; Falone, A; Fitze, H; Geiselhart, C; Guetg, M W; Hämmerli, F; Hauff, A; Heiniger, M; Higgs, C; Hugentobler, W; Hunziker, S; Janser, G; Kalantari, B; Kalt, R; Kim, Y; Koprek, W; Korhonen, T; Krempaska, R; Laznovsky, M; Lehner, S; Pimpec, F Le; Lippuner, T; Lutz, H; Mair, S; Marcellini, F; Marinkovic, G; Menzel, R; Milas, N; Pal, T; Pollet, P; Portmann, W; Rezaeizadeh, A; Ritt, S; Rohrer, M; Schär, M; Schebacher, L; Scherrer, St; Schmidt, V Schlott T; Schulz, L; Smit, B; Stadler, M; Steffen, B; Stingelin, L; Sturzenegger, W; Treyer, D M; Trisorio, A; Tron, W; Vicario, C; Zennaro, R; Zimoch, D

    2016-01-01

    The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and testbed for the development and realization of SwissFEL, the X-ray Free-Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including a transverse deflecting rf cavity. It delivered electron bunches of up to 200 pC charge and up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of an FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultra-low-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics meas...

  14. Design Studies for a High-Repetition-Rate FEL Facility at LBNL.

    Energy Technology Data Exchange (ETDEWEB)

    CORLETT, J.; BELKACEM, A.; BYRD, J. M.; FAWLEY, W.; KIRZ, J.; LIDIA, S.; MCCURDY, W.; PADMORE, H.; PENN, G.; POGORELOV, I.; QIANG, J.; ROBIN, D.; SANNIBALE, F.; SCHOENLEIN, R.; STAPLES, J.; STEIER, C.; VENTURINI, M.; WAN, W.; WILCOX, R.; ZHOLENTS, A.

    2007-10-04

    Lawrence Berkeley National Laboratory (LBNL) is working to address the needs of the primary scientific Grand Challenges now being considered by the U.S. Department of Energy, Office of Basic Energy Sciences: we are exploring scientific discovery opportunities, and new areas of science, to be unlocked with the use of advanced photon sources. A partnership of several divisions at LBNL is working to define the science and instruments needed in the future. To meet these needs, we propose a seeded, high-repetition-rate, free-electron laser (FEL) facility. Temporally and spatially coherent photon pulses, of controlled duration ranging from picosecond to sub-femtosecond, are within reach in the vacuum ultraviolet (VUV) to soft X-ray regime, and LBNL is developing critical accelerator physics and technologies toward this goal. We envision a facility with an array of FELs, each independently configurable and tunable, providing a range of photon-beam properties with high average and peak flux and brightness.

  15. Two-color infrared FEL facility employing a 250-MeV linac injector of Saga synchrotron light source

    CERN Document Server

    Tomimasu, T; Koga, N; Hashiguchi, Y; Ochiai, Y; Ishibashi, M

    2001-01-01

    A two-color infrared free electron laser (FEL) facility is proposed. This FEL facility will employ a new 250-MeV linac injector of the Saga synchrotron light source (SLS). The linac has two operation modes: short macropulse mode of 1 mu s at 250 MeV is for injection to a 1.4-GeV storage ring and long macropulse mode of 13 mu s at 40 MeV is for the two-color FEL facility. The two-color FEL uses a single electron beam and simultaneously provides both infrared (IR) and far-IR laser pulses for pump-probe studies of quantum-well structures and studying vibrational relaxation of molecules. The Saga SLS will be operated in 2004 to promote material science, bio-medical and industrial applications in Kyushu.

  16. Harmonic cascade FEL designs for LUX, a facility for ultrafast x-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, John; Fawley, William; Penn, Gregory; Wan, Weishi; Zholents, A.; Reinsch, M.; Wurtele, Jonathan

    2004-08-25

    LUX is a design study to develop concepts for future ultrafast x-ray facilities. Presently, LUX is based on an electron beam accelerated to {approx}3-GeV energy in a superconducting, recirculating linac. Included in the design are multiple free-electron laser (FEL) beamlines which use the harmonic cascade approach to produce coherent XUV and soft X-ray emission beginning with a strong input seed at {approx}200-nm wavelength obtained from a ''conventional'' laser. Each cascade module generally operates in the low-gain regime and is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a ''virgin'' pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse. For a given cascade, the output photon energy can be selected over a wide range by varying the seed laser wavelength and the field strength in the undulators. We present numerical simulation results, as well as those from analytical models, to examine certain aspects of the predicted FEL performance. We also discuss lattice considerations pertinent to harmonic cascade FELs, some sensitivity studies and requirements on the undulator alignment, and temporal pulse evolution initiated by short input radiation seeds.

  17. Emittance measurements and minimization at the SwissFEL Injector Test Facility

    Directory of Open Access Journals (Sweden)

    Eduard Prat

    2014-10-01

    Full Text Available The emittance of the electron beam is crucial for Free-Electron Laser facilities: it has a strong influence on the lasing performance and on the total length of the accelerator. We present our procedure to measure and minimize the projected and slice emittance at the SwissFEL Injector Test Facility. The normalized slice emittance resolution achieved is about 3 nm and the longitudinal resolution is about 13 fs, with measurement errors estimated to be below 5%. After performing a full optimization we have obtained, for uncompressed beams, a slice emittance of about 200 nm for a beam charge of 200 pC, and a slice emittance of about 100 nm for 10 pC. These values are consistent with our simulations and are well below the requirements of the SwissFEL under construction at the Paul Scherrer Institute. At these bunch charges our measured slice emittances are, to our knowledge, the lowest reported so far for an electron linear accelerator.

  18. 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.

  19. Comparison of different undulator schemes with superimposed alternating gradients for the VUV-FEL at the TESLA Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Pflueger, J.; Nikitina, Y.M. [DESY/HASYLAB, Hamburg (Germany)

    1995-12-31

    For the VUV-FEL at the TESLA Test Facility an undulator with a total length of 30 m is needed. In this study three different approaches to realize an undulator with a sinusoidal plus a superimposed quadrupolar field were studied with the 3D code MAFIA.

  20. Electron Beam Diagnostic Based on a Short Seeded FEL

    CERN Document Server

    Graves, W; Kaertner, Franz X; Zwart, T

    2005-01-01

    The optical properties of an FEL amplifier are sensitively dependent on the electron beam current profile, energy spread, and transverse emittance. In this paper we consider using a short FEL amplifier operating on a low harmonic of a visible-IR input seed as a mildly destructive electron beam diagnostic able to measure these properties for sub-ps time slices. The optical methods are described as well as a planned implementation of the device for the FERMI@Elettra XUV FEL under construction at Sincrotrone Trieste, including its fiber-based seed laser closely coupled with the facility timing system, undulator parameters, and requirements on the electron and FEL pulses. This diagnostic is conveniently integrated with a "laser heater" designed to increase the very low electron beam energy spread produced by a photoinjector in order to avoid space charge and coherent synchrotron radiation instabilities.

  1. Instrumentation for Longitudinal Beam Gymnastics in FEL's and at the CLIC Test Facility 3

    CERN Document Server

    Lefèvre, T; Bravin, E; Burger, S; Corsini, R; Döbert, S; Soby, L; Tecker, F A; Urschutz, P; Welsch, C P; Alesini, D; Biscari, C; Buonomo, B; Coiro, O; Ghigo, A; Marcellini, F; Preger, B; Dabrowski, A; Velasco, M; Craievich, P; Ferianis, M; Veronese, M; Ferrari, A

    2008-01-01

    Built at CERN by an international collaboration, the CLIC Test Facility 3 (CTF3) aims at demonstrating the feasibility of a high luminosity 3 TeV e+-e- collider by the year 2010. One of the main issues to be demonstrated is the generation of a high average current (30 A) high frequency (12 GHz) bunched beam by means of RF manipulation. At the same time, Free Electron Lasers (FEL) are developed in several places all over the world with the aim of providing high brilliance photon sources. These machines rely on the production of high peak current electron bunches. The required performances put high demands on the diagnostic equipment and innovative longitudinal monitors have been developed during the past years. This paper gives an overview of the longitudinal instrumentation developed at ELETTRA and CTF3, where a special effort was made in order to implement at the same time non-intercepting devices for online monitoring, and destructive diagnostics which have the advantage of providing more detailed informati...

  2. FEL Design Studies at LBNL: Activities and Plans

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, John N.; Fawley, W.; Lidia, S.; Padmore, H.; Penn, G.; Pogorelov, I.; Qiang, J.; Sannibale, F.; Staples, J.; Steier, C.; Venturini, M.; Wan, W.; Wilcox, R.; Zholents, A.

    2007-03-01

    LBNL staff are currently pursuing R&D for future x-ray FELs, and participate in two FEL construction projects. Our strategy is to address the most fundamental challenges, which are the cost-drivers and performance limitations of FEL facilities. An internally funded R&D program is aimed at investigating accelerator physics and technologies in three key areas: (1) Theoretical study, modeling, and experimental development of low emittance, high quantum efficiency cathodes; (2) Design studies of electron beam delivery systems, including emittance manipulations, high-resolution modeling of 6-D phase space, and low-emittance beam transport; and (3) Design studies of optical manipulations of electron beams for seeded and SASE FELs, providing short x-ray pulses of variable duration, synchronous with the seed and pump laser sources, and also long transform-limited pulses with a narrow bandwidth. Design studies of means for production of attosecond x-ray pulses at various wavelengths. We are collaborators in the FERMI{at}Elettra seeded FEL facility under construction at Sincrotrone Trieste, Italy, participating in accelerator design and FEL physics studies, and mechanical and electrical engineering. We are participating in the LCLS project at SLAC, implementing our design of stabilized timing and synchronization systems. Here we outline our long-term objectives, and current activities.

  3. Multipurpose end-station for coherent diffraction imaging and scattering at FERMI@Elettra free-electron laser facility.

    Science.gov (United States)

    Capotondi, Flavio; Pedersoli, Emanuele; Bencivenga, Filippo; Manfredda, Michele; Mahne, Nicola; Raimondi, Lorenzo; Svetina, Cristian; Zangrando, Marco; Demidovich, Alexander; Nikolov, Ivaylo; Danailov, Miltcho; Masciovecchio, Claudio; Kiskinova, Maya

    2015-05-01

    The Diffraction and Projection Imaging (DiProI) beamline at FERMI, the Elettra free-electron laser (FEL), hosts a multi-purpose station that has been opened to users since the end of 2012. This paper describes the core capabilities of the station, designed to make use of the unique features of the FERMI-FEL for performing a wide range of static and dynamic scattering experiments. The various schemes for time-resolved experiments, employing both soft X-ray FEL and seed laser IR radiation are presented by using selected recent results. The ongoing upgrade is adding a reflection geometry setup for scattering experiments, expanding the application fields by providing both high lateral and depth resolution.

  4. Gain length dependence on phase shake in the VUV-FEL at the TESLA Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Pflueger, J. [DESY/HASYLAB, Hamburg (Germany); Schneidmiller, E.A. [Automatic Systems Corporation, Samara (Russian Federation); Pierini, P. [INFN, Milano (Italy)

    1995-12-31

    The TTF VUV FEL, which is in its design stage at DESY, consists of a 30 m long SASE FEL which will radiate around 6 nm, driven by a superconducting linac with final energy of 1 GeV. One of the important issues in its design is the undulator performance, which is studied in this paper. The present setup, including FODO lattice, is discussed in this paper. Results of simulations, including the realistic wiggler field errors and beam stearing, are presented. Dependence of the performance, in particular the gain and saturation length as well as the saturation peak power, on the wiggler field errors is discussed.

  5. Fermi

    Data.gov (United States)

    National Aeronautics and Space Administration — Fermi is a powerful space observatory that will open a wide window on the universe. Gamma rays are the highest-energy form of light, and the gamma-ray sky is...

  6. Development of a pump-probe facility with sub-picosecond time resolution combining a high-power ultraviolet regenerative FEL amplifier and a soft X-ray SASE FEL

    CERN Document Server

    Faatz, B; Feldhaus, J; Krzywinski, J; Pflüger, J; Rossbach, J; Saldin, E L; Schneidmiller, E A; Yurkov, M V

    2001-01-01

    This paper presents the conceptual design of a high power radiation source with laser-like characteristics in the ultraviolet spectral range at the TESLA Test Facility (TTF). The concept is based on the generation of radiation in a regenerative FEL amplifier (RAFEL). The RAFEL described in this paper covers a wavelength range of 200-400 nm and provides 200 fs pulses with 2 mJ of optical energy per pulse. The linac operates at 1% duty factor and the average output radiation power exceeds 100 W. The RAFEL will be driven by the spent electron beam leaving the soft X-ray FEL, thus providing minimal interference between these two devices. The RAFEL output radiation has the same time structure as the X-ray FEL and the UV pulses are naturally synchronized with the soft X-ray pulses from the TTF FEL. Therefore, it should be possible to achieve synchronization close to the duration of the radiation pulses (200 fs) for pump-probe techniques using either an UV pulse as a pump and soft X-ray pulse as a probe, or vice ver...

  7. Large-Scale Timing Distribution and RF-Synchronization for FEL Facilities

    CERN Document Server

    Kim, Jung Won; Kaertner, Franz X; Muecke, Oliver; Perrott, Michael

    2004-01-01

    For future advances in accelerator physics in general and seeding of FELs in particular, precise synchronization between seed radiation, low-level RF-systems and photo-injector laser is required. Typical synchronization methods based on direct photodetection are limited by the detector nonlinearities, which lead to amplitude-to-phase conversion and introduce timing jitter. A new synchronization scheme for extraction of low jitter RF-signals from optical pulse trains distributed by mode-locked lasers is proposed. It is robust against photodetector nonlinearities. The scheme is based on a transfer of timing information into an intensity imbalance between the two output beams from a Sagnac-loop interferometer. As a first experimental demonstration, sub-100 fs timing jitter between the extracted 2 GHz RF-signal and the 100 MHz optical pulse train from a mode-locked Ti:sapphire laser is demonstrated. Numerical simulations show that scaling to sub-femtosecond precision is possible. Together with mode-locked fiber l...

  8. The Low Density Matter (LDM) beamline at FERMI: optical layout and first commissioning.

    Science.gov (United States)

    Svetina, Cristian; Grazioli, Cesare; Mahne, Nicola; Raimondi, Lorenzo; Fava, Claudio; Zangrando, Marco; Gerusina, Simone; Alagia, Michele; Avaldi, Lorenzo; Cautero, Giuseppe; de Simone, Monica; Devetta, Michele; Di Fraia, Michele; Drabbels, Marcel; Feyer, Vitaliy; Finetti, Paola; Katzy, Raphael; Kivimäki, Antti; Lyamayev, Viktor; Mazza, Tommaso; Moise, Angelica; Möller, Thomas; O'Keeffe, Patrick; Ovcharenko, Yevheniy; Piseri, Paolo; Plekan, Oksana; Prince, Kevin C; Sergo, Rudi; Stienkemeier, Frank; Stranges, Stefano; Coreno, Marcello; Callegari, Carlo

    2015-05-01

    The Low Density Matter (LDM) beamline has been built as part of the FERMI free-electron laser (FEL) facility to serve the atomic, molecular and cluster physics community. After the commissioning phase, it received the first external users at the end of 2012. The design and characterization of the LDM photon transport system is described, detailing the optical components of the beamline.

  9. 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.

  10. FELs, nice toys or efficient tools?

    Science.gov (United States)

    van der Meer, A. F. G.

    2004-08-01

    An FEL is an intrinsically interesting device and pushing its performance presents a natural challenge to a physicist. Nonetheless, the main justification for doing FEL research is of course its potential as a unique, versatile source of radiation to be employed for something useful. After 25 years of FEL research, one may wonder how efficient these tools have become. In this paper, I will reflect on this issue from the perspective of 10 years of operation of FELIX as a user facility.

  11. Contributions to the FEL2005 conference

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, O. (comp.)

    2005-07-01

    The following topics were dealt with: First lasing at 32 nm of the VUV-FEL at DESY, properties of the radiation from VUV-FEL at DESY, accelerator lay out and physics of X-ray free-electron lasers, bunch compression stability dependence on RF parameters, undulator systems and photon diagnostic for the European XFEL project, electron beam characterization at PITZ and the VUV-FEL at DESY, high precision optical synchronization systems for X-ray free electron lasers, optical laser synnchronized for the DESY VUV-FEL for two-color pump probe experiments, properties of the third harmonic of the SASE FEL radiation, detector response and beam line transmission measurements with far-infrared radiation, upgrades of the laser beam-line at PITZ, bunch length measurements using a Martin-Puplett interferometer at the VUV-FEL, next generation synchronization system for the VUV-FEL at DESY, transverse electron beam diagnostics at the VYV-FEL at DESY, the infrared undulator project at the VUV-FEL, misconceptions regarding second harmonic generation in X-ray free-electron lasers, influence of an energy chirp on SASE FEL operation, design considerations for the 4GLS XUV-FEL, broadband single shot spectrometer, commissioning of TTF2 bunch compressors for 20 fs SASE source, observation of femtosecond bunch length using a transverse deflecting structure, measurement of slice-emittance using a transverse deflecting structure, the injector of the VUV-FEL at DESY, spectral decoding electro-optic measurements for longitudinal bunch diagnostics at the DESY VUV-FEL, longitudinal phase space studies at PITZ, modelling the transverse phase space and core emittance studies at PITZ, measurements of thermal emittance for cesium telluride photocathodes at PITZ, status and first results from the upgraded PITZ facility, commissioning of the SPARC movable emittance meter and its first operation at PITZ. (HSI)

  12. Design and simulation challenges for FERMI@elettra

    Science.gov (United States)

    Di Mitri, S.; Allaria, E.; Badano, L.; Bontoiu, C.; Cornacchia, M.; Craievich, P.; Danailov, M.; De Ninno, G.; Diviacco, B.; Ferrando, O.; Ferry, S.; Iazzourene, F.; Milton, S. V.; Penco, G.; Spampinati, S.; Trovo', M.; Veronese, M.; Fawley, W.; Lidia, S.; Penn, G.; Qiang, J.; Sonnad, K. G.; Venturini, M.; Warnock, R.; Zholents, A. A.; Pogorelov, I. V.; Borland, M.; Bassi, G.; Ellison, J. A.; Heinemann, K.; Fiorito, R.; Shkvarunets, A.; Tobin, J. C.

    2009-09-01

    FERMI@elettra is a fourth-generation light source user facility under construction at the Elettra Laboratory in Trieste, Italy. The high-quality 1.2 GeV electron beam drives two-seeded Free Electron Lasers (FELs) in the wavelength range 100-10 nm. Wavelength tunability, variable polarization and higher electron beam energies to reach even shorter output wavelengths are also in the machine delivery plan. This paper describes the physics processes that have been modelled to simulate FERMI@elettra and the computer codes used to optimize the machine design. The paper focuses on several design challenges and how these translate into modelling and simulation challenges.

  13. Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti-Sa Laser Produced in Xe Gas

    CERN Document Server

    Lambert, G

    2005-01-01

    In order to reach very short wavelengths in systems based on Free Electrons Laser (FEL), and to have a more compact, fully coherent and tunable source, a particular seeding configuration is studied here. It is foreseen to test it as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). SCSS phase 1 is a linac-based FEL project, providing a compact SASE source with high brightness in the X-ray range. The external laser source, which is employed, is straightfully in the XUV range, the 13th harmonic of a Ti:Sa femtosecond laser (61.5 nm), generated in Xe gas. This harmonic can be now easily generated by focusing the Ti: Sa laser (25 mJ, 10 Hz, 100 fs) on a 10 Hz pulsed Xe gas cell. This High order Harmonics Generation (HHG) process provides us with a VUV beam with intense (1 μJ) and ultra-short (50 fs) properties.

  14. Novel active signal compression in low-noise analog readout at future X-ray FEL facilities

    Science.gov (United States)

    Manghisoni, M.; Comotti, D.; Gaioni, L.; Lodola, L.; Ratti, L.; Re, V.; Traversi, G.; Vacchi, C.

    2015-04-01

    This work presents the design of a low-noise front-end implementing a novel active signal compression technique. This feature can be exploited in the design of analog readout channels for application to the next generation free electron laser (FEL) experiments. The readout architecture includes the low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time variant shaper used to process the signal at the preamplifier output and a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC). The channel will be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future XFEL machines. The choice of a 65 nm CMOS technology has been made in order to include all the building blocks in the target pixel pitch of 100 μm. This work has been carried out in the frame of the PixFEL Project funded by the Istituto Nazionale di Fisica Nucleare (INFN), Italy.

  15. Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY

    CERN Document Server

    Hahn, U; Pflüger, J; Rüter, M; Schmidt, G; Trakhtenberg, E

    2000-01-01

    Three vacuum chambers for the VUV SASE FEL undulator sections at the TESLA Test Facility (TTF) were designed, built, tested and installed. Each chamber is 4.5 m long and of 11.5 mm thick. The inner diameter of the beam pipe is 9.5 mm. The rectangular chamber profile with a width of 128 mm is used to integrate beam position monitors and steerers. This is needed to provide a good overlap between the electron and the photon beam over the entire undulator length. The chambers are built in an aluminum extrusion technology developed for the insertion device vacuum chambers of the Advanced Photon Source. After manufacturing, special processing was performed to reach low outgassing rates (<1x10 sup - sup 1 sup 1 mbar centre dot l/s centre dot cm sup 2) and particle-free chambers. Mounting of the chambers at TTF were performed under clean room conditions better class 100.

  16. A Cherenkov radiator for FEL-synchronized VUV-pulses at a linac-based FEL

    NARCIS (Netherlands)

    Goloviznin, V. V.; Oepts, D.; van der Wiel, M. J.

    1997-01-01

    A possible way to carry out two-color IR+VUV pump-probe experiments at linac-based FELs is proposed. The idea is to supply an FEL facility with a gas cell filled with helium or hydrogen, so that the electron beam, upon passage through the undulator, could be used to generate ultraviolet Cherenkov

  17. Fermi Timing and Synchronization System

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, R.; Staples, J.; Doolittle, L.; Byrd, J.; Ratti, A.; Kaertner, F.X.; Kim, J.; Chen, J.; Ilday, F.O.; Ludwig, F.; Winter, A.; Ferianis, M.; Danailov, M.; D' Auria, G.

    2006-07-19

    The Fermi FEL will depend critically on precise timing of its RF, laser and diagnostic subsystems. The timing subsystem to coordinate these functions will need to reliably maintain sub-100fs synchronicity between distant points up to 300m apart in the Fermi facility. The technology to do this is not commercially available, and has not been experimentally demonstrated in a working facility. Therefore, new technology must be developed to meet these needs. Two approaches have been researched by different groups working with the Fermi staff. At MIT, a pulse transmission scheme has been developed for synchronization of RF and laser devices. And at LBL, a CW transmission scheme has been developed for RF and laser synchronization. These respective schemes have advantages and disadvantages that will become better understood in coming years. This document presents the work done by both teams, and suggests a possible system design which integrates them both. The integrated system design provides an example of how choices can be made between the different approaches without significantly changing the basic infrastructure of the system. Overall system issues common to any synchronization scheme are also discussed.

  18. X-ray beam splitting design for concurrent imaging at hard X-ray FELs and synchrotron facilities

    Energy Technology Data Exchange (ETDEWEB)

    Oberta, P., E-mail: peter.oberta@rigaku.com [Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i., Na Slovance 2, Praha 8, CZ-18221 (Czech Republic); Rigaku, Novodvorská 994, Praha 4, CZ-14221 (Czech Republic); Mokso, R. [Swiss Light Source, Paul Scherrer Institut, Villigen, CH-5232 Villigen (Switzerland)

    2013-11-21

    A new configuration of diffractive–refractive optics for beam splitting is investigated. The set-up can be applied to perform imaging with two beams simultaneously. It brings advantages toward dynamic studies using image guided diffraction or fluorescence spectroscopy. The optimal energy range of operation for the beam-splitter is between 7 keV and 24 keV, reaching best efficiency at an energy of 10 keV. Due to the long focusing distances (several tens of meters) created by the diffractive–refractive optics and the higher refraction efficiency in the softer energy range, the presented set-ups are ideal for hard X-ray FEL sources.

  19. FEL system for gamma-gamma collider at TESLA

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2001-01-01

    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 TTF (TESLA Test Facility) 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 a radiation of TW level with a wavelength of 1 mu m. Optimization of the FEL amplifier is performed with a three-dimensional, time-dependent simulation code FAST.

  20. Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti Sa Laser (61.5 nm) Produced in Xe Gas

    CERN Document Server

    Lambert, G; Boutu, W; Breger, P; Couprie, M E; Garzella, D; Merdji, H; Monchicourt, P; Salieres, P

    2005-01-01

    In order to reach very short wavelengths in FEL, and to have a more compact, fully coherent and tunable source, a particular seeding configuration is foreseen to be tested as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). The external source is the 13th harmonic (61.5 nm) of a Ti: Sa laser (25 mJ, 10 Hz, 100 fs) generated in 10 Hz pulsed Xe gas cell. The harmonic generation process provides us with a intense (1 μJ) and ultra-short (50 fs) VUV beam. The design of the experiment implantation is discussed, taken into account the performances of the generation process, the focusing of the selected harmonic into the modulator, and the resistance of the optical components. Besides one should consider the vacuum needs, the geometrical problems and the mechanics for the under UHV mirrors translation. One first chamber is dedicated to the harmonic generation. A second one is used for spectral selection and adaptation of the harmonic in the modulator. F...

  1. Generating polarization controllable FELs at Dalian coherent light source

    CERN Document Server

    Zhang, T; Wang, D; Zhao, Z T; Zhang, W Q; Wu, G R; Dai, D X; Yang, X M

    2013-01-01

    The property of the FEL polarization is of great importance to the user community. FEL pulses with ultra-high intensity and flexible polarization control ability will absolutely open up new scientific realms. In this paper, several polarization control approaches are presented to investigate the great potential on Dalian coherent light source, which is a government-approved novel FEL user facility with the capability of wavelength continuously tunable in the EUV regime of 50-150 nm. The numerical simulations show that both circularly polarized FELs with highly modulating frequency and 100 microjoule level pulse energy could be generated at Dalian coherent light source.

  2. A feasibility study of TAC IR-FEL project

    Energy Technology Data Exchange (ETDEWEB)

    Aksakal, Huesnue, E-mail: aksakal@cern.c [Nigde University, Department of Physics, Faculty of Letter and Science, 51240 Nigde (Turkey); Arikan, Ertan [Nigde University, Department of Physics, Faculty of Letter and Science, 51240 Nigde (Turkey)

    2010-08-21

    We have performed preliminary simulation of amplifier mode operation of Turkish accelerator complex (TAC) infrared free electron laser (IR-FEL) facility which is designed to operate in oscillator mode. FEL power values of amplifier mode are explored using 3D SIMPLEX 1.3 (X-ray FEL Practical Simulator) simulation code and it is argued that the same or higher amount of power of TAC IR-FEL planing to obtain in the oscillator mode, could be obtained in the amplifier mode, using same undulator and electron beam parameters with a small modification.

  3. First Results from the DUV-FEL Upgrade at BNL

    CERN Document Server

    Wang, Xijie; Murphy, James; Pinayev, Igor; Rakowsky, George; Rose, James; Shaftan, Timur; Sheehy, Brian; Skaritka, John; Wu, Zilu; Yu Li Hua

    2005-01-01

    The DUV-FEL at BNL is the world’s only facility dedicated to laser-seeded FEL R&D and its applications. Tremendous progress was made in both HGHG FEL and its applications in the last couple years.*,** In response to the requests of many users to study chemical science at the facility, the DUV-FEL linac was upgraded from 200 to 300 MeV to enable the HGHG FEL to produce 100 uJ pulses of 100 nm light. This will establish the DUV FEL as a premier user facility for ultraviolet radiation and enable state-of-the-art gas phase photochemistry research. The upgraded facility will also make possible key R&D experiments such as higher harmonic HGHG (n>5) that would lay the groundwork for future X-ray FEL based on HGHG. The upgraded HGHG FEL will operate at the 4th harmonic with the seed laser at either 800 nm or 400nm. The increase of the electron beam energy will be accomplished by installing a 5th linac cavity and two 45 MW klystrons. New HGHG modulator and dispersion sections vacuum chambers w...

  4. Innovative FEL schemes using variable-gap undulators

    Science.gov (United States)

    Schneidmiller, E. A.; Yurkov, M. V.

    2017-06-01

    We discuss theoretical background and experimental verification of advanced schemes for X-ray FELs using variable gap undulators (harmonic lasing self-seeded FEL, reverse taper etc.) Harmonic lasing in XFELs is an opportunity to extend operating range of existing and planned X-ray FEL user facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam which is easier to handle due to the suppressed fundamental. Another interesting application of harmonic lasing is Harmonic Lasing Self-Seeded (HLSS) FEL that allows to improve longitudinal coherence and spectral power of a SASE FEL. Recently this concept was successfully tested at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. That was also the first experimental demonstration of harmonic lasing in a high-gain FEL and at a short wavelength (before it worked only in infrared FEL oscillators). Another innovative scheme that was tested at FLASH2 is the reverse tapering that can be used to produce circularly polarized radiation from a dedicated afterburner with strongly suppressed linearly polarized radiation from the main undulator. This scheme can also be used for an efficient background-free production of harmonics in an afterburner. Experiments on the frequency doubling that allowed to reach the shortest wavelength at FLASH as well as on post-saturation tapering to produce a record intencity in XUV regime are also discussed.

  5. The Dresden 100 T/10 ms project a high magnetic field facility at an IR-FEL

    CERN Document Server

    Dorr, M; Eschrig, H; Fischer, F; Fulde, P; Groessinger, R; Grunberger, W; Handstein, A; Hinz, D; Kratz, R; Krug, H; Loewenhaupt, M; Müller, K H; Pobell, F; Schultz, L; Siegel, H; Steglich, F; Vergés, P

    2002-01-01

    Summary form only given. We have proposed to build a 100 T/10 ms, 70 T/100 ms, 60 T/1 s pulsed field user facility with a 50 MJ capacitor bank at the Forschungszentrum Rossendorf near Dresden. This would provide the appealing possibility to have access to Zeeman energies in the energy range of the infrared free-electron-lasers (5 mu m to 150 mu m; 2 ps; cw; >10 W) now under construction at the radiation source ELBE (superconducting electron linear accelerator; 40 MeV; 1 m A; 2 ps; cw) in Rossendorf. The work is accompanied by computer simulations of the planned coil systems, of the power supply, and by the development of high-strength conductors aiming at a tensile strength of about 1.5 GPa at sigma approximately= sigma /sub Cu//2 (microcomposite CuAg alloys and Cu-steel macro compounds). With a view of gaining experience in the construction and operation of pulsed magnets, a pilot pulsed field laboratory was established at the Institute of Solid State and Materials Research Dresden (IFW Dresden). The laborat...

  6. Two FEL`s in one

    Energy Technology Data Exchange (ETDEWEB)

    Epp, V. [Tomsk Pedagogical Institute (Russian Federation); Nikitin, M. [Tomsk Polytechnical Univ. (Russian Federation)

    1995-12-31

    A new scheme for a FEL operation is proposed. The conventional principle of FEL operation is means that the electron bunch passes through the interaction area of FEL only in one direction. We suggest another possible layout which implies that the electron bunch makes a turn after leaving the wiggler and entries the wiggler at the same end. Actually the wiggler is a kind of a bridge between two storage rings. The electron bunches on the orbit are expected to be adjusted in the way that after one of them leaves the wiggler, another one enters in the opposite direction and in the proper phase with the wave pulse emitted by the previous bunch. So the electron bunch comes in interaction with the amplified electromagnetic wave in both directions i.e. twice per period. It is especially important for the short wavelength FELs, because each reflection from the mirror causes a significant losses of the wave magnitude. The proposed design gives one interaction per each reflection instead of one interaction per two reflections in the traditional scheme. Another way to realize the suggested principle of operating is to insert the wiggler in the electron-positron storage ring. But this layout can be less efficient because of low intensity of the positron beam. The comparison study of radiation from different types of described double wigglers is fulfilled. The synchronization problems are discussed in this paper.

  7. FERMI&Elettra Accelerator Technical Optimization Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cornacchia, M.; Craievich, P.; Di Mitri, S.; /Sincrotrone Trieste; Pogorelov, I.; Qiang, J.; Venturini, M.; Zholents, A.; /LBL, Berkeley; Wang, D.; /MIT; Warnock, R.; /SLAC

    2007-04-30

    This chapter describes the accelerator physics aspects, the engineering considerations and the choice of parameters that led to the accelerator design of the FERMI Free-Electron-Laser. The accelerator (also called the ''electron beam delivery system'') covers the region from the exit of the injector to the entrance of the first FEL undulator. The considerations that led to the proposed configuration were made on the basis of a study that explored various options and performance limits. This work follows previous studies of x-ray FEL facilities (SLAC LCLS [1], DESY XFEL [2], PAL XFEL [3], MIT [4], BESSY FEL [5], LBNL LUX [6], Daresbury 4GLS [7]) and integrates many of the ideas that were developed there. Several issues specific to harmonic cascade FELs, and that had not yet been comprehensively studied, were also encountered and tackled. A particularly difficult issue was the need to meet the requirement for high peak current and small slice energy spread, as the specification for the ratio of these two parameters (that defines the peak brightness of the electron beam) is almost a factor of two higher than that of the LCLS's SASE FEL. Another challenging aspect was the demand to produce an electron beam with as uniform as possible peak current and energy distributions along the bunch, a condition that was met by introducing novel beam dynamics techniques. Part of the challenge was due to the fact that there were no readily available computational tools to carry out reliable calculations, and these had to be developed. Most of the information reported in this study is available in the form of scientific publications, and is partly reproduced here for the convenience of the reader.

  8. 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.

  9. R&D Requirements, RF Gun Mode Studies, FEL-2 Steady-StateStudies, Preliminary FEL-1 Time-Dependent Studies, and Preliminary LayoutOption Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, John; Corlett, John; Doolittle, Larry; Fawley, William; Lidia, Steven; Penn, Gregory; Ratti, Alex; Staples, John; Wilcox Russell; Wurtele, Jonathan; Zholents, Alexander

    2005-10-01

    This report constitutes the third deliverable of LBNLs contracted role in the FERMI {at} Elettra Technical Optimization study. It describes proposed R&D activities for the baseline design of the Technical Optimization Study, initial studies of the RF gun mode-coupling and potential effects on beam dynamics, steady-state studies of FEL-2 performance to 10 nm, preliminary studies of time-dependent FEL-1 performance using electron bunch distribution from the start-to-end studies, and a preliminary investigation of a configuration with FEL sinclined at a small angle from the line of the linac.

  10. Feasibility of an XUV FEL Oscillator Driven by a SCRF Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H.; Freund, H. P.; Reinsch, M.

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermi National Accelerator Laboratory. Using a1-ms-long macropulse composed of up to 3000 micropulses, and with beam energies projected from 45 to 800 MeV, the possibility for an extreme ultraviolet (XUV) free-electron laser oscillator (FELO) with the higher energy is evaluated. We have used both GINGER with an oscillator module and the MEDUSA/OPC code to assess FELO saturation prospects at 120 nm, 40 nm, and 13.4 nm. The results support saturation at all of these wavelengths which are also shorter than the demonstrated shortest wavelength record of 176 nm from a storage-ring-based FELO. This indicates linac-driven FELOs can be extended into this XUV wavelength regime previously only reached with single-pass FEL configurations.

  11. Diagnostics and Instrumentation for FEL

    CERN Document Server

    Couprie, M E

    2001-01-01

    Free Electron Laser are coherent sources of radiation based on the interaction of a relativistic electron beam in an undulator field. According to the energy of the accelerator, they presently cover a wide spectral range, from the infra-red to the VUV. FELs combine the diagnostics of typical laser systems (for the measurement of spectral and temporal characteristics, the transverse mode pattern, the polarisation) and the diagnostics of relativistic electron beams. The electron beam is characterised in order to evaluate and control the FEL performances, but also in order to measure the effect of the FEL on the electron beam. The FEL characteristics are monitored with various types of detectors, depending mainly on the spectral range. Diagnostics for Linac based Infra Red FELs and storage ring FELs in the UV-VUV will be described. Particular instrumentation, required for FEL operation, such as the optical resonator, possible diagnostics inside the undulator will also be analysed.

  12. A compact FEL upconverter of coherent radiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Marshall, T.C. [Columbia Univ., New York, NY (United States)

    1995-12-31

    The objective is to generate a powerful millimeter-wave FEL signal in a single pass, using a coherent microwave source (24GHz) to prebunch the electron beam for a harmonically-related wave (72GHz). We use the Columbia FEL facility, operating the electron beam at 600kV, 100A; undulator period = 1.85cm and 250G (K = 0.25); electron beam diameter = 3mm inside a 8.5 mm ID drift tube; guiding field of 8800G. Under these conditions, both the microwave signal (5kW input) and the millimeter signal will show travelling-wave gain in the TE11 mode. We report initial experimental results for the millimeter wave spectrum and find an overall power gain of {approximately}20 for the 24GHz input wave. Also presented will be numerical solutions of the wave growth using the FEL equations with slippage. This device has the advantage of producing a high-power FEL output in a single-pass travelling-wave configuration, obtaining a millimeter wave which is phase-referenced to a coherent laboratory source.

  13. Present and next steps of the JAERI superconducting rf linac based FEL program

    Energy Technology Data Exchange (ETDEWEB)

    Minehara, E.J.; Yamauchi, T.; Sugimoto, M. [FEL Laboratory at Tokai, Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (JP)] (and others)

    2000-03-01

    The JAERI superconducting rf linac based FEL has successfully been lased to produce a 0.3 kW FEL light and 100 kW or larger electron beam output in quasi continuous wave operation in 1999. The 1 kW class output as our present program goal will be achieved to improve the optical out coupling method in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. As our next 5 year program goal is the 100 kW class FEL light and a few tens MW class electron beam output in average, quasi continuous wave operation of the light and electron beam will be planned in the JAERI superconducting rf linac based FEL facility. Conceptual design options needed for such a very high power operation and shorter wavelength light sources will be discussed to improve and to upgrade the exciting facility. (author)

  14. FEL-accelerator related diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Jordan; David Douglas; Stephen V. Benson; Pavel Evtuschenko

    2007-08-02

    Free Electron Lasers (FEL) present a unique set of beam parameters to the diagnostics suite. The FEL requires characterization of the full six dimensional phase space of the electron beam at the wiggler and accurate alignment of the electron beam to the optical mode of the laser. In addition to the FEL requirements on the diagnostics suite, the Jefferson Lab FEL is operated as an Energy Recovered Linac (ERL) which imposes additional requirements on the diagnostics. The ERL aspect of the Jefferson Lab FEL requires that diagnostics operate over a unique dynamic range and operate with simultaneous transport of the accelerated and energy recovered beams. This talk will present how these challenges are addressed at the Jefferson Lab FEL.

  15. Tapered undulators for SASE FELs

    CERN Document Server

    Fawley, W M; Vinokurov, N A

    2002-01-01

    We discuss the use of tapered undulators to enhance the performance of free-electron lasers (FELs) based upon self-amplified spontaneous emission, where the radiation tends to have a relatively broad bandwidth and limited temporal coherence. Using the polychromatic FEL simulation code GINGER, we numerically demonstrate the effectiveness of tapered undulators for parameters corresponding to the Argonne low-energy undulator test line FEL and the proposed linac coherent light source.

  16. STARS A Two Stage High Gain Harmonic Generation FEL Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    M. Abo-Bakr; W. Anders; J. Bahrdt; P. Budz; K.B. Buerkmann-Gehrlein; O. Dressler; H.A. Duerr; V. Duerr; W. Eberhardt; S. Eisebitt; J. Feikes; R. Follath; A. Gaupp; R. Goergen; K. Goldammer; S.C. Hessler; K. Holldack; E. Jaeschke; Thorsten Kamps; S. Klauke; J. Knobloch; O. Kugeler; B.C. Kuske; P. Kuske; A. Meseck; R. Mitzner; R. Mueller; M. Neeb; A. Neumann; K. Ott; D. Pfluckhahn; T. Quast; M. Scheer; Th. Schroeter; M. Schuster; F. Senf; G. Wuestefeld; D. Kramer; Frank Marhauser

    2007-08-01

    BESSY is proposing a demonstration facility, called STARS, for a two-stage high-gain harmonic generation free electron laser (HGHG FEL). STARS is planned for lasing in the wavelength range 40 to 70 nm, requiring a beam energy of 325 MeV. The facility consists of a normal conducting gun, three superconducting TESLA-type acceleration modules modified for CW operation, a single stage bunch compressor and finally a two-stage HGHG cascaded FEL. This paper describes the faciliy layout and the rationale behind the operation parameters.

  17. Industrial Applications of High Average Power FELS

    CERN Document Server

    Shinn, Michelle D

    2005-01-01

    The use of lasers for material processing continues to expand, and the annual sales of such lasers exceeds $1 B (US). Large scale (many m2) processing of materials require the economical production of laser powers of the tens of kilowatts, and therefore are not yet commercial processes, although they have been demonstrated. The development of FELs based on superconducting RF (SRF) linac technology provides a scaleable path to laser outputs above 50 kW in the IR, rendering these applications economically viable, since the cost/photon drops as the output power increases. This approach also enables high average power ~ 1 kW output in the UV spectrum. Such FELs will provide quasi-cw (PRFs in the tens of MHz), of ultrafast (pulsewidth ~ 1 ps) output with very high beam quality. This talk will provide an overview of applications tests by our facility's users such as pulsed laser deposition, laser ablation, and laser surface modification, as well as present plans that will be tested with our upgraded FELs. These upg...

  18. Harmonic lasing in X-ray FELs

    CERN Document Server

    Schneidmiller, E A

    2012-01-01

    Harmonic lasing in a free electron laser with a planar undulator (under the condition that the fundamental frequency is suppressed) might be a cheap and efficient way of extension of wavelength ranges of existing and planned X-ray FEL facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam which is easier to handle due to the suppressed fundamental frequency. In this paper we perform a parametrization of the solution of the eigenvalue equation for lasing at odd harmonics, and present an explicit expression for FEL gain length, taking into account all essential effects. We propose and discuss methods for suppression of the fundamental harmonic. We also suggest a combined use of harmonic lasing and lasing at the retuned fundamental wavelength in order to reduce bandwidth and to increase brilliance of X-ray beam at saturation. Considering 3rd harmonic lasing as a practical example, we come to the conclusion that it is much more robust...

  19. Harmonic cascade FEL designs for LUX

    Energy Technology Data Exchange (ETDEWEB)

    Penn, G.; Reinsch, M.; Wurtele, J.; Corlett, J.N.; Fawley, W.M.; Zholents, A.; Wan, W.

    2004-07-16

    LUX is a design concept for an ultrafast X-ray science facility, based on an electron beam accelerated to GeV energies in are circulating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 200-250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.

  20. Electron Beam Characterization at PITZ and the VUV-FEL at DESY

    CERN Document Server

    Honkavaara, K

    2005-01-01

    The VUV-FEL being commissioned at DESY Hamburg is a user facility for SASE FEL radiation in the VUV wavelength range. The quality of the high brightness electron beam driving the VUV-FEL plays an important role for the performance of the facility. Prior to installation, the electron photo-injector of the VUV-FEL has been fully tested and characterized at the PITZ photo injector test facility at DESY Zeuthen, dedicated to develop high brightness electron sources for FEL projects like the VUV-FEL and the XFEL. We summarize the results on transverse emittance optimization at PITZ and report on the upgrade of the PITZ facility presently under construction. Results on transverse emittance optimization and measurements at the VUV-FEL are presented. Projected emittances around 1.4 mm mrad for 90% of a 1 nC bunch have been regularly measured. In addition, recent measurements of the longitudinal bunch profile after compression using a transverse deflecting cavity are presented.

  1. Application of a PWFA to an X-ray FEL

    CERN Document Server

    Israeli, Yasmine; Reiche, Sven; Pedrozzi, Marco; Muggli, Patric

    2016-01-01

    There is a growing demand for X-ray Free-electron lasers (FELs) in various science fields, in particular for those with short pulses, larger photon fluxes and shorter wavelengths. The level of X-ray power and the pulse energy depend on the amount of electron bunch energy. Increasing the latter will increase the power of the radiating X-rays. Using numerical simulations we explore the possibility of using a plasma wakefield accelerator (PWFA) scheme to increase the electron beam energy of an existing FEL facility without significantly increasing the accelerator length. In this paper we use parameters of the SwissFEL beam. The simulations are carried out in 2D cylindrical symmetry using the code OSIRIS. Initial results show an energy gain of ~2 GeV after propagation of 0.5 m in the plasma with a relative energy spread of ~1%.

  2. A high-average-power FEL for industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, H.F.; Benson, S.; Bisognano, J.

    1995-12-31

    CEBAF has developed a comprehensive conceptual design of an industrial user facility based on a kilowatt UV (150-1000 nm) and IR (2-25 micron) FEL driven by a recirculating, energy-recovering 200 MeV superconducting radio-frequency (SRF) accelerator. FEL users{endash}CEBAF`s partners in the Laser Processing Consortium, including AT&T, DuPont, IBM, Northrop-Grumman, 3M, and Xerox{endash}plan to develop applications such as polymer surface processing, metals and ceramics micromachining, and metal surface processing, with the overall effort leading to later scale-up to industrial systems at 50-100 kW. Representative applications are described. The proposed high-average-power FEL overcomes limitations of conventional laser sources in available power, cost-effectiveness, tunability and pulse structure. 4 refs., 3 figs., 2 tabs.

  3. FEL simulations for the LCLS

    CERN Document Server

    Nuhn, H D

    1999-01-01

    A first design study report has recently been completed (The LCLS Design Study Group, LCLS Design Study Report, April 1998, SLAC-R-521) for the linac coherent light source (LCLS), a proposal to build an X-ray free electron laser (FEL) at the Stanford Linear Accelerator Center (SLAC) as a single pass self-amplified spontaneous emission (SASE) amplifier. The proposal includes the use of a very low emittance electron beam accelerated up to 15 GeV by the last third of the SLAC linac to produce sub-picosecond X-ray pulses with high brightness and full transverse coherence in a 112-m long undulator. Many aspects of the FEL design have been analyzed with FEL simulation codes. The paper discusses some of the results of these aspects, i.e. temporal X-ray pulse structure and power spectrum, trajectory errors and effects of undulator beam tube wakefields.

  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. Coherence Improvement of the BESSY HGHG FEL Radiation

    CERN Document Server

    Abo-Bakr, M; Meseck, A

    2005-01-01

    BESSY proposes a soft X-ray free electron laser (FEL) multi-user facility. It will consist of three undulator lines, each based on a cascaded High-Gain Harmonic-Generation (HGHG) scheme. With a seed laser, tunable between 230 nm and 460 nm, the desired output radiation wavelength range from 1.24 nm to 51 nm can be covered. Signal to noise ratio and coherence of the HGHG FEL radiation degrades quadratically with the harmonic number. For the short-wavelength BESSY-FEL line, operating on the 225th harmonic of the seed, a cure to this effect and maintaining the coherence is to improve the spectral purity of the output radiation by implementation of a "non-dispersive double-monochromator" system between two HGHG stages. Layout and parameters of such a monochromator section are described. To separate the electron beam path from the optical devices a bypass section is needed. Its design is presented and influences on the electron beam dynamics are discussed. Simulations of the full cascaded HGHG FEL, using the resto...

  6. Ultrafast Coherent Control and Characterization of Surface Reactions using FELs

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Hirohito; Nordlund, Dennis a Nilsson, Anders; /SLAC, SSRL

    2005-09-30

    The microscopic understanding of reactions at surfaces requires an in-depth knowledge of the dynamics of elementary processes on an ultrafast timescale. This can be accomplished using an ultrafast excitation to initiate a chemical reaction and then probe the progression of the reaction with an ultrashort x-ray pulse from the FEL. There is a great potential to use atom-specific spectroscopy involving core levels to probe the chemical nature, structure and bonding of species on surfaces. The ultrashort electron pulse obtained in the linear accelerator to feed the X-ray FEL can also be used for generation of coherent synchrotron radiation in the low energy THz regime to be used as a pump. This radiation has an energy close to the thermal excitations of low-energy vibrational modes of molecules on surfaces and phonons in substrates. The coherent THz radiation will be an electric field pulse with a certain direction that can collectively manipulate atoms or molecules on surfaces. In this respect a chemical reaction can be initiated by collective atomic motion along a specific reaction coordinate. If the coherent THz radiation is generated from the same source as the X-ray FEL radiation, full-time synchronization for pump-probe experiments will be possible. The combination of THz and X-ray spectroscopy could be a unique opportunity for FEL facilities to conduct ultrafast chemistry studies at surfaces.

  7. FEL Applications in EUV Lithography

    CERN Document Server

    Goldstein, M; Shroff, Y A; Silverman, P J; Williams, D

    2005-01-01

    Semiconductor industry growth has largely been made possible by regular improvements in lithography. State of the art lithographic tools cost upwards of twenty five million dollars and use 0.93 numerical aperture projection optics with 193nm wavelengths to pattern features for 45 nm node development. Scaling beyond the 32 nm feature size node is expected to require extreme ultraviolet (EUV) wavelength light. EUV source requirements and equipment industry plasma source development efforts are reviewed. Exploratory research on a novel hybrid klystron and high gain harmonic generation FEL with oblique laser seeding will be disclosed. The opportunity and challenges for FELs to serve as a second generation (year 2011-2013) source technology in the semiconductor industry are presented.

  8. High Average Power Optical FEL Amplifiers

    CERN Document Server

    Ben-Zvi, I; Litvinenko, V

    2005-01-01

    Historically, the first demonstration of the FEL was in an amplifier configuration at Stanford University. There were other notable instances of amplifying a seed laser, such as the LLNL amplifier and the BNL ATF High-Gain Harmonic Generation FEL. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance a 100 kW average power FEL. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting energy recovery linacs combine well with the high-gain FEL amplifier to produce unprecedented average power FELs with some advantages. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Li...

  9. The formation of transverse coherence in SASE FELs

    CERN Document Server

    Saldin, E L; Yurkov, M V

    1999-01-01

    This report presents a fully three-dimensional study of the amplification process in the self amplified spontaneous emission (SASE) free electron laser. Investigations are based on the data obtained with the three-dimensional, time-dependent FEL simulation code FAST. Analysis of the data shows that the statistical properties of the radiation can be described with Gaussian statistics. In particular, fluctuations of the instantaneous radiation intensity at one space point follow the negative exponential law, while the finite-time integrals of the radiation intensity (both in space and in time) follow a gamma-distribution. Numerical examples presented in the paper correspond to the 70 nm SASE FEL under construction at the TESLA test facility at DESY.

  10. Locking Lasers to RF in an Ultra Fast FEL

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, R.; Huang, G.; Doolittle, L.; White, W.; Frisch, J.; Coffee, R.

    2010-01-02

    Using a novel, phase-stabilized RF-over-fiber scheme, they transmit 3GHz over 300m with 27fs RMS error in 250kHz bandwidth over 12 hours, and phase lock a laser to enable ultrafast pump-probe experiments. Free-electron lasers (FELs) are capable of producing short-duration (< 10fs), high-energy X-ray pulses for a range of scientific applications. The recently activated Linac Coherent Light Source (LCLS) FEL facility at SLAC will support experiments which require synchronized light pulses for pump-probe schemes. They developed and operated a fiber optic RF transmission system to synchronize lasers to the emitted X-ray pulses, which was used to enable the first pump-probe experiments at the LCLS.

  11. A HIGH REPETITION RATE VUV-SOFT X-RAY FEL CONCEPT

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.; Byrd, J.; Fawley, W.M.; Gullans, M.; Li, D.; Lidia,S.M.; Padmore, H.; Penn, G.; Pogorelov, I.; Qiang, J.; Robin, D.; Sannibale, F.; Staples, J.W.; Steier, C.; Venturini, M.; Virostek, S.; Wan, W.; Wells, R.; Wilcox, R.; Wurtele, J.; Zholents, A.

    2007-06-24

    We report on design studies for a seeded FEL light source that is responsive to the scientific needs of the future. The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, reduced gain length in the FEL, utilization of harmonics to attain shorter wavelengths, and precise synchronization of the x-ray pulse with seed laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FEL's, each producing high average brightness, tunable over the VUV-soft x-ray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhanced-SASE (ESASE), seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands.

  12. In-pixel conversion with a 10 bit SAR ADC for next generation X-ray FELs

    Energy Technology Data Exchange (ETDEWEB)

    Lodola, L., E-mail: luca.lodola01@universitadipavia.it [Università degli Studi di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Batignani, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Benkechkache, M.A. [TIFPA INFN, I-38123 Trento (Italy); University Constantine 1, Department of Electronics in the Science and Technology Faculty, I-25017 Constantine (Algeria); Bettarini, S.; Casarosa, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Comotti, D. [Università degli Studi di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Dalla Betta, G.F. [Università di Trento, Dipartimento di Ingegneria Industriale, I-38123 Trento (Italy); TIFPA INFN, I-38123 Trento (Italy); Fabris, L. [INFN Sezione di Pavia, I-27100 Pavia (Italy); Università di Bergamo, Dipartimento di Ingegneria e Scienze Applicate, I-24044 Dalmine (Italy); Forti, F. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Grassi, M. [Università degli Studi di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Latreche, S. [University Constantine 1, Department of Electronics in the Science and Technology Faculty, I-25017 Constantine (Algeria); and others

    2016-07-11

    This work presents the design of an interleaved Successive Approximation Register (SAR) ADC, part of the readout channel for the PixFEL detector. The PixFEL project aims at substantially advancing the state-of-the-art in the field of 2D X-ray imaging for applications at the next generation Free Electron Laser (FEL) facilities. For this purpose, the collaboration is developing the fundamental microelectronic building blocks for the readout channel. This work focuses on the design of the ADC carried out in a 65 nm CMOS technology. To obtain a good tradeoff between power consumption, conversion speed and area occupation, an interleaved SAR ADC architecture was adopted.

  13. In-pixel conversion with a 10 bit SAR ADC for next generation X-ray FELs

    Science.gov (United States)

    Lodola, L.; Batignani, G.; Benkechkache, M. A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Dalla Betta, G. F.; Fabris, L.; Forti, F.; Grassi, M.; Latreche, S.; Malcovati, P.; Manghisoni, M.; Mendicino, R.; Morsani, F.; Paladino, A.; Pancheri, L.; Paoloni, E.; Ratti, L.; Re, V.; Rizzo, G.; Traversi, G.; Vacchi, C.; Verzellesi, G.; Xu, H.

    2016-07-01

    This work presents the design of an interleaved Successive Approximation Register (SAR) ADC, part of the readout channel for the PixFEL detector. The PixFEL project aims at substantially advancing the state-of-the-art in the field of 2D X-ray imaging for applications at the next generation Free Electron Laser (FEL) facilities. For this purpose, the collaboration is developing the fundamental microelectronic building blocks for the readout channel. This work focuses on the design of the ADC carried out in a 65 nm CMOS technology. To obtain a good tradeoff between power consumption, conversion speed and area occupation, an interleaved SAR ADC architecture was adopted.

  14. FELS, nice toys or efficient tools?

    NARCIS (Netherlands)

    van der Meer, A. F. G.

    2004-01-01

    An FEL is an intrinsically interesting device and pushing its performance presents a natural challenge to a physicist. Nonetheless, the main justification for doing FEL research is of course its potential as a unique, versatile source of radiation to be employed for something useful. After 25 years

  15. Derivation of FEL Gain Using Wakefield Approach

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, Gennady V.

    2003-05-27

    We describe the one-dimensional SASE FEL instability using the wake approach. First, we obtain an expression for the longitudinal 1-D wake in a helical undulator. We then show that taking into account the retardation effect in the Vlasov equation with the proper wake leads to the correct result for the FEL instability, in agreement with the traditional theory.

  16. Seeded quantum FEL at 478 keV

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marc [Max-Planck-Institut fuer Quantenoptik, Garching (Germany); Thirolf, Peter; Seggebrock, Thorben [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Habs, Dietrich [Max-Planck-Institut fuer Quantenoptik, Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany)

    2012-07-01

    We present for the first time a concept for a seeded {gamma} quantum Free Electron Laser (QFEL) at 478 keV (transition in {sup 7}Li). To produce a highly intense and coherent {gamma} beam, we intend to use a seeded FEL scheme. Important for the production of a highly brilliant and coherent {gamma} beam are novel refractive {gamma} lenses for focusing and an efficient monochromator, allowing to generate a very intense and coherent seed beam. To realize such a coherent {gamma} beam at 478 keV (1/38 A), it is suitable to use a quantum FEL design based on a new ''asymmetric'' laser-electron Compton back scattering scheme as pursued for the MeGaRay and ELI-NP facilities. Here the pulse length of the laser is much longer than the electron bunch length, equivalent to a {gamma}-FEL with laser wiggler. The coherence of a seeded QFEL can open up totally new areas of fundamental physics and applications. Especially, 478 keV can be attractive for ''green energy'' and life-science research, such as the detection of Li deposition in the brain for manic-depressive psychosis treatment with high spatial resolution or isotope-specific nuclear waste management and treatment.

  17. Enrico Fermi

    Institute of Scientific and Technical Information of China (English)

    李琳

    2006-01-01

    Enrico Fermi was born in Rome on 29th September, 1901. He attended a local grammar school, and in 1918, he won a fellowship of the Scuola Normale Superiore of Pisa, where he gained his doctor’s degree in physics in 1922, with Professor Puccianti. In 1923, he was awarded a scholarship from the Italian Government. With a Rockefeller Fellowship, in 1924, he moved to Leyden, and later that same year he returned to Italy to occupy for two

  18. The EIS beamline at the seeded free-electron laser FERMI

    Science.gov (United States)

    Simoncig, A.; Mincigrucci, R.; Principi, E.; Bencivenga, F.; Calvi, A.; Foglia, L.; Kurdi, G.; Raimondi, L.; Manfredda, M.; Mahne, N.; Gobessi, R.; Gerusina, S.; Fava, C.; Zangrando, M.; Matruglio, A.; Dal Zilio, S.; Masciotti, V.; Masciovecchio, C.

    2017-05-01

    Among the fourth-generation light sources, the Italian free-electron laser (FEL) FERMI is the only one operating in the high-gain harmonic generation (HGHG) seeding mode. FERMI delivers pulses characterized by a quasi transform limited temporal structure, photon energies lying in the extreme ultra-violet (EUV) region, supreme transversal and longitudinal coherences, high peak brilliance, and full control of the polarization. Such state of the art performances recently opened the doors to a new class of time-resolved spectroscopies, difficult or even impossible to be performed using self-amplified spontaneous sources (SASE) light sources. FERMI is currently equipped with three operating beamlines opened to external users (DiProI, LDM and EIS), while two more are under commissioning (MagneDYN and TeraFERMI). Here, we present the recent highlights of the EIS (Elastic and Inelastic Scattering) beamline, which has been purposely designed to take full advantage from the coherence, the intensity, the harmonics content, and the temporal duration of the pulses. EIS is a flexible experimental facility for time-resolved EUV scattering experiments on condensed matter systems, consisting of two independent end-stations. The first one (EIS-TIMEX) aims to study materials in metastable and warm dense matter (WDM) conditions, while the second end-station (EIS-TIMER) is fully oriented to the extension of four-wave mixing (FWM) spectroscopies towards the EUV spectral regions, trying to reveal the behavior of matter in portions of the mesoscopic regime of exchanged momentum impossible to be probed using conventional light sources.

  19. Undulator beamline optimization with integrated chicanes for X-ray free-electron-laser facilities.

    Science.gov (United States)

    Prat, Eduard; Calvi, Marco; Ganter, Romain; Reiche, Sven; Schietinger, Thomas; Schmidt, Thomas

    2016-07-01

    An optimization of the undulator layout of X-ray free-electron-laser (FEL) facilities based on placing small chicanes between the undulator modules is presented. The installation of magnetic chicanes offers the following benefits with respect to state-of-the-art FEL facilities: reduction of the required undulator length to achieve FEL saturation, improvement of the longitudinal coherence of the FEL pulses, and the ability to produce shorter FEL pulses with higher power levels. Numerical simulations performed for the soft X-ray beamline of the SwissFEL facility show that optimizing the advantages of the layout requires shorter undulator modules than the standard ones. This proposal allows a very compact undulator beamline that produces fully coherent FEL pulses and it makes possible new kinds of experiments that require very short and high-power FEL pulses.

  20. Design Formulas for VUV and X-Ray FELs

    CERN Document Server

    Saldin, Evgeny L; Yurkov, Mikhail V

    2004-01-01

    Simple formulas for optimization of VUV and X-ray SASE FELs are presented. The FEL gain length and the optimal beta-function are explicitly expressed in terms of the electron beam and undulator parameters. The FEL saturation length is estimated taking into account energy diffusion due to quantum fluctuations of the undulator radiation. Examples of the FEL optimization are given. Parameters of a SASE FEL, operating at the Compton wavelength, are suggested.

  1. FEL development at the Budker Institute of Nuclear Physics

    Science.gov (United States)

    Vinokurov, N. A.

    1993-07-01

    There are three different FEL projects at the Budker Institute of Nuclear Physics: 1) the FEL on the VEPP-3 storage ring which operates in the visible and ultraviolet region; 2) the high power FEL using a racetrack microtron recuperator (this machine will provide an average power of about tens of kilowatt in the infrared region); and 3) the compact infrared FEL project, using a microton, and a powerful FEL on a dedicated superconducting storage ring, which is under consideration now.

  2. Enhancing FEL Power with Phase Shifters

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel; /Stanford U.; Chao, Alex; Huang, Zhirong; /SLAC

    2010-07-30

    Tapering the undulator parameter is a well-known method for maintaining the resonant condition past saturation, and increasing Free Electron Laser (FEL) efficiency. In this paper, we demonstrate that shifting the electron bunch phase relative to the radiation is equivalent to tapering the undulator parameter. Using discrete phase changes derived from optimized undulator tapers for the Linac Coherent Light Source (LCLS) x-ray FEL, we show that appropriate phase shifts between undulator sections can reproduce the power enhancement of undulator tapers. Phase shifters are relatively easy to implement and operate, and could be used to aid or replace undulator tapers in optimizing FEL performance.

  3. Fused rock from Köfels, Tyrol

    Science.gov (United States)

    Milton, Daniel J.

    1964-01-01

    The vesicular glass from Köfels, Tyrol, contains grains of quartz that have been partially melted but not dissolved in the matrix glass. This phenomenon has been observed in similar glasses formed by friction along a thrust fault and by meteorite impact, but not in volcanic glasses. The explosion of a small nuclear device buried behind a steep slope produced a geologic structure that is a good small-scale model of that at Köfels. Impact of a large meteorite would have an effect analogous to that of a subsurface nuclear explosion and is the probable cause of the Köfels feature.

  4. 76 FR 1197 - Detroit Edison Company, FERMI 2; Exemption

    Science.gov (United States)

    2011-01-07

    ... COMMISSION Detroit Edison Company, FERMI 2; Exemption 1.0 Background Detroit Edison Company (DECo) (the licensee) is the holder of Facility Operating License No. NFP-43 which authorizes operation of the Fermi 2... exemption stated that a tornado swept across the Fermi 2 property on June 6, 2010, and that the...

  5. 75 FR 15748 - Detroit Edison Company; Fermi 2; Exemption

    Science.gov (United States)

    2010-03-30

    ... COMMISSION Detroit Edison Company; Fermi 2; Exemption 1.0 Background Detroit Edison Company (the licensee) is the holder of Facility Operating License No. NPF-43, which authorizes operation of Fermi 2. The...- September 11, 2001, security orders. It is from five of these new requirements that Fermi 2 now seeks...

  6. Start-To-End Injector and Linac Tolerance Studies for the BESSY FEL

    CERN Document Server

    Abo-Bakr, Michael; Knobloch, Jens; Kuske, Bettina; Meseck, Atoosa

    2004-01-01

    BESSY is proposing a Soft X-ray FEL user facility in Berlin, delivering short and stabile photon pulses in the wavelength range of 62 nm < λ < 1.2 nm by applying up to four cascaded High Gain Harmonic Generation (HGHG) stages. For optimization of the FEL performance of the cascaded HGHG stages extensive Start-to-End (S2E) simulations have been carried out. In order to test the quality of the chosen configuration with respect to the sensitivity against various error sources tolerance studies from the injector to the linac end have been performed. Procedures and results of these studies will be presented.

  7. Simulation of FEL pulse length calculation with THz streaking method

    Energy Technology Data Exchange (ETDEWEB)

    Gorgisyan, I., E-mail: ishkhan.gorgisyan@psi.ch [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, Route Cantonale, 1015 Lausanne (Switzerland); Ischebeck, R.; Prat, E.; Reiche, S. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Rivkin, L. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, Route Cantonale, 1015 Lausanne (Switzerland); Juranić, P., E-mail: ishkhan.gorgisyan@psi.ch [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2016-04-02

    Simulation of THz streaking of photoelectrons created by X-ray pulses from a free-electron laser and reconstruction of the free-electron laser pulse lengths. Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump–probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision.

  8. Recent Results from and Future Plans for the VISA II SASE FEL

    CERN Document Server

    Andonian, Gerard; Babzien, Marcus; Ben-Zvi, Ilan; Boscolo, Ilario; Cialdi, Simone; Ferrario, Massimo; Flacco, Alessandro Federico; Frigola, Pedro; Huang, Jung Y; Litvinenko, Vladimir N; Murokh, Alex; Palumbo, Luigi; Pellegrini, Claudio; Reiche, Sven; Rosenzweig, James E; Travish, Gil; Vicario, Carlo; Yakimenko, Vitaly

    2005-01-01

    As the promise of X-ray Free Electron Lasers (FEL) comes close to realization, the creation and diagnosis of ultra-short pulses is of great relevance in the SASE FEL (Self-Amplified Spontaneous Emission) community. The VISA II (Visible to Infrared SASE Amplifier) experiment entails the use of a chirped electron beam to drive a high gain SASE FEL at the Accelerator Test Facility (ATF) in Brookhaven National Labs (BNL). The resulting ultra-short pulses will be diagnosed using an advanced FROG (Frequency Resolved Optical Gating) technique, as well as a double differential spectrum (angle/wavelength) diagnostic. Implementation of sextupole corrections to the longitudinal aberrations affecting the high energy-spread chirped beam during transport to the VISA undulator is studied. Start-to-end simulations, including radiation diagnostics, are discussed. Initial experimental results involving a highly chirped beam transported without sextupole correction, the resulting high gain lasing, and computational analysis are...

  9. Design and Test of Wire-Scanners for SwissFEL

    CERN Document Server

    Orlandi, G L; Brands, H; Heimgartner, P; Ischebeck, R; Kammerer, A; Löhl, F; Lüscher, R; Mohanmurthy, P; Ozkan, C; Schlott, V; Schulz, L; Rippstein, B; Seiler, C; Trovati, S; Valitutti, P; Zimoch, D

    2016-01-01

    The SwissFEL light-facility will provide coherent X-rays in the wavelength region 7-0.7 nm and 0.7-0.1 nm. In SwissFEL, view-screens and wire-scanners will be used to monitor the transverse profile of a 200/10pC electron beam with a normalized emittance of 0.4/0.2 mm.mrad and a final energy of 5.8 GeV. Compared to view screens, wire-scanners offer a quasi-non-destructive monitoring of the beam transverse profile without suffering from possible micro-bunching of the electron beam. The main aspects of the design, laboratory characterization and beam-test of the SwissFEL wire-scanner prototype will be discussed.

  10. Obtaining high degree of circular polarization at X-ray FELs via a reverse undulator taper

    Energy Technology Data Exchange (ETDEWEB)

    Schneidmiller, E.A.; Yurkov, M.V.

    2013-08-15

    Baseline design of a typical X-ray FEL undulator assumes a planar configuration which results in a linear polarization of the FEL radiation. However, many experiments at X-ray FEL user facilities would profit from using a circularly polarized radiation. As a cheap upgrade one can consider an installation of a short helical (or cross-planar) afterburner, but then one should have an efficient method to suppress powerful linearly polarized background from the main undulator. In this paper we propose a new method for such a suppression: an application of the reverse taper in the main undulator. We discover that in a certain range of the taper strength, the density modulation (bunching) at saturation is practically the same as in the case of non-tapered undulator while the power of linearly polarized radiation is suppressed by orders of magnitude. Then strongly modulated electron beam radiates at full power in the afterburner. Considering SASE3 undulator of the European XFEL as a practical example, we demonstrate that soft X-ray radiation pulses with peak power in excess of 100 GW and an ultimately high degree of circular polarization can be produced. The proposed method is rather universal, i.e. it can be used at SASE FELs and seeded (self-seeded) FELs, with any wavelength of interest, in a wide range of electron beam parameters, and with any repetition rate. It can be used at different X-ray FEL facilities, in particular at LCLS after installation of the helical afterburner in the near future.

  11. FEL options for power beaming

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.J.; Zholents, A.A.; Zolotorev, M.S. [Lawrence Berkeley National Lab., CA (United States); Vinokurov, N.A. [Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-10-01

    The demand for the output power of communication satellites has been increasing exponentially. The satellite power is generated from solar panels which collect the sunlight and convert it to electrical power. The power per satellite is limited due to the limit in the practical size of the solar panel. One way to meet the power demand is to employ multiple satellites (up to 10) per the internationally agreed-upon ``slot`` in the geosynchronous earth orbit (GEO). However, this approach is very expensive due to the high cost of sending a satellite into a GEO orbit. An alternative approach is power beaming, i.e., to illuminate the solar panels with high power, highly-directed laser beams from earth. The power beaming generates more power per satellite for the same area of the solar panel. The minimum optical beam power, interesting for power beaming application, is P{sub L} = 200kW. The wavelength is chosen to be {lambda} = 0.84 {micro}m, so that it is within one of the transmission windows of the air, and at the same time near the peak of the photo-voltaic conversion efficiency of Si, which is the commonly used material for the solar panels. Free electron lasers (FELs) are well suited for the power beaming application because they can provide high power with coherent wavefront, but without high energy density in media. In this article the authors discuss some principal issues, such as the choice of accelerator and electron gun, the choice of beam parameters, radiation hazards, technological availability, and overall efficiency and reliability of the installation. They also attempt to highlight the compromise between the cost of the primary installation, the operation cost, and the choice of technology, and its maturity. They then present several schemes for the accelerator-FEL systems based on RF accelerators. The initial electron beam accelerator up to the energy of a few MeV is more or less common for all these schemes.

  12. Summary of the working group on FEL theory

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C.

    1984-01-01

    The working group on FEL theory dedicated most of its discussions to topics relevant to the high gain regime in a free electron laser. In addition the area of interest was mainly restricted to FELs for the production of XUV radiation (<1000 A). A list of the topics that were felt to be relevant is: (1) characterization of the FEL high gain regime; (2) the amplified spontaneous emission mode of operation (ASE); (3) superradiance in FELs; (4) diffraction effects for high gain FELs; (5) noise and start-up; (6) coherence properties of the radiation for the ASE and superradiant FELS. 9 references.

  13. Optical tailoring of xFEL beams

    Energy Technology Data Exchange (ETDEWEB)

    West, Gavin [SLAC National Accelerator Lab., Menlo Park, CA (United States); Coffee, R. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    There is an inherent exibility unique to free electron lasers (FELs) that lends well to experimental approaches normally too difficult for other light sources to accomplish. This includes the ability to optically shape the electron bunch prior to final its acceleration for the final FEL process. Optical pulse shaping of the electron bunch can enable both femtosecond and attosecond level FEL pulse control. Pulse shaping is currently implemented, not optically but mechanically, in LCLS-I with an adjustable foil slit that physically spoils the momentum phase of the electron bunch. This selectively suppresses the downstream FEL process ofspoiled electrons. Such a mechanical spoiling method fails for both the soft x-ray regime as well as the high repetition rates that are planned in LCLS-II. Our proposed optical spoiling method circumvents this limitation by making use of the existing ultrafast laser beam that is typically used for adjusting the energy spread for the initial electron bunch. Using Fourier domain shaping we can nearly arbitrarily shape the laser pulses to affect the electron bunch. This can selectively spoil electrons within each bunch. Here we demonstrate the viability of this approach with a programmable acousto-optic dispersive filter. This method is not only well suited for LCLS-II but also has several advantages over mechanical spoiling, including lack of radiation concerns, experiment specific FEL pulse shapes, and real-time adjustment for applications that require high duty-cycle variation such as lock-in amplification of small signals.

  14. Development of intense terahertz coherent synchrotron radiation at KU-FEL

    Energy Technology Data Exchange (ETDEWEB)

    Sei, Norihiro, E-mail: sei.n@aist.go.jp [Research Institute for Measurement and Analytical Instrumentation, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Zen, Heishun; Ohgaki, Hideaki [Institute for Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2016-10-01

    We produced intense coherent synchrotron radiation (CSR) in the terahertz (THz) region using an S-band linac at the Kyoto University Free Electron Laser (KU-FEL), which is a mid-infrared free-electron laser facility. The CSR beam was emitted from short-pulse electron bunches compressed by a 180° arc, and was transferred to air at a large solid angle of 0.10 rad. The measured CSR energy was 55 μJ per 7 μs macropulse, and KU-FEL was one of the most powerful CSR sources in normal conducting linear accelerator facilities. The CSR spectra were measured using an uncooled pyroelectric detector and a Michelson-type interferometer designed specifically for the KU-FEL electron beam, and had a maximum at a frequency of 0.11 THz. We found that adjusting the energy slit enhanced the CSR energy and shortened the electron beam bunch length in the CSR spectra measurements. Our results demonstrated that the efficient use of the energy slit can help improve the characteristics of CSR. - Highlights: • We have developed intense coherent synchrotron radiation (CSR) at KU-FEL. • The elevation angle of the CSR was correctly measured by a new technique. • The CSR power extracted to the air was 55 μJ per 7 μs macropulse. • It was demonstrated that an energy slit was effective to improve the CSR properties.

  15. Availability Performance and Considerations for LCLS X-Ray FEL at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Allen, W.B.; Brachmann, A.; Colocho, W.; Stanek, M.; Warren, J.; /SLAC

    2011-08-16

    The Linac Coherent Light Source (LCLS) is an X-ray Free Electron Laser (FEL) facility located at the SLAC National Accelerator Laboratory. LCLS has been in operation since spring 2009, and it has completed its 3rd user run. LCLS is the first in its class of X-ray FEL user facilities, and presents different availability challenges compared to storage ring light sources. This paper presents recent availability performance of the FEL as well as factors to consider when defining the operational availability figure of merit for user runs. During LCLS [1] user runs, an availability of 95% has been set as a goal. In run III, LCLS photon and electron beam systems achieved availabilities of 94.8% and 96.7%, respectively. The total availability goal can be distributed among subsystems to track performance and identify areas that need attention in order to maintain and improve hardware reliability and operational availability. Careful beam time accounting is needed to understand the distribution of down time. The LCLS complex includes multiple experimental hutches for X-ray science, and each user program has different requirements of a set of parameters that the FEL can be configured to deliver. Since each user may have different criteria for what is considered 'acceptable beam', the quality of the beam must be considered to determine the X-ray beam availability.

  16. Properties of the Third Harmonic of the SASE FEL Radiation

    CERN Document Server

    Saldin, E L; Schneidmiller, E

    2005-01-01

    Recent theoretical and experimental studies have shown that SASE FEL with a planar undulator holds a potential for generation of relatively strong coherent radiation at the third harmonic of the fundamental frequency. Here we present detailed study of the nonlinear harmonic generation in SASE FEL obtained with time-dependent FEL simulation code FAST. Using similarity techniques we present universal dependencies for temporal, spectral, and statistical properties of the third harmonic radiation from SASE FEL.

  17. Investigation of a 2-Colour Undulator FEL Using Puffin

    CERN Document Server

    Campbell, L T; Reiche, S

    2013-01-01

    Initial studies of a 2-colour FEL amplifier using one monoenergetic electron beam are presented. The interaction is modelled using the unaveraged, broadband FEL code Puffin. A series of undulator modules are tuned to generate two resonant frequencies along the FEL interaction and a self-consistent 2-colour FEL interaction at widely spaced non-harmonic wavelengths at 1nm and 2.4nm is demonstrated.

  18. Low Emittance X-FEL Development

    CERN Document Server

    Li, K S B; Anghel, A; Bakker, R J; Böge, M; Candel, A E; Dehler, M; Ganter, R; Gough, C; Ingold, G; Leemann, S C; Pedrozzi, M; Raguin, J Y; Rivkin, L; Schlott, V; Streun, A; Wrulich, A F

    2005-01-01

    The Paul Scherrer Institute (PSI) in Switzerland currently develops a Low-Emittance electron-Gun (LEG) based on field-emitter technology [1]. The target is a normalized transverse emittance of 5 10(-8) m rad or less. Such a source is particularly interesting for FELs that target wavelengths below 0.3 nm since it permits a reduction of the required beam-energy and hence, a reduction of the construction- and operational costs of X-ray FELs. That is, for the case that this initial low emittance can be maintained throughout the accelerator. Here we present a concept for a 0.1 nm X-FEL based on LEG, which can be located close to the Swiss Light Source (SLS). Special attention goes to the maintenance of the emittance during the process of acceleration and bunch-compression, in particular in the regimes where either space-charge forces or coherent-synchrotron radiation are of importance.

  19. Design study on the merger for BXERL-FEL

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiong-Wei; WANG Shu-Hong; CHEN Sen-Yu

    2009-01-01

    In North China, there is a preliminary proposal for ERL-FEL light source (BXERL-FEL) with its aim at "one machine, two purposes" (the XFEL and ERL work simultaneously). One of the key technologies is the merger section. In this paper, we give the physical design of the merger section for BXERL-FEL which merges three kinds of electron beam.

  20. First Lasing at the ELBE mid-IR FEL

    CERN Document Server

    Michel, Peter

    2004-01-01

    First lasing of the mid infrared FEL at ELBE was achieved on May 7, 2004. The Radiation Source ELBE at the Forschungszentrum Rossendorf in Dresden is currently under transition from commissioning to regular user operation. Presently the electron linac produces an up to 18 MeV, 1 mA (cw) electron beam which is alotted to generate various kinds of secondary radiation. After the successful commissioning of the bremsstrahlung and channeling-X-ray facilities during 2003 stable lasing has now been observed in the IR range (15 to 22 μm). The oscillator FEL is equipped with two planar undulator units, both consisting of 34 hybrid permanent magnet periods of 27.3 mm (Krms = 0.3 - 0.8). The distance between the two parts is variable and the gaps can be adjusted and tapered independently. At 19.6 µm an optical power of 3W was out-coupled in a macro pulse of 0.6 ms duration using an electron beam energy of 16.1 MeV and an energy spread of less than 100 keV; the micropulse charge was 50 pC and its width slightly a...

  1. Characteristics of the Duke/OK-4 storage ring FEL and gamma-ray source

    Science.gov (United States)

    Park, Seong Hee

    The Duke/OK-4 storage ring is a dedicated device for driving a short wavelength Free Electron Laser (FEL). In addition, Compton scattering of the laser light from the circulating electron beam products a semi-monochromatic γ-ray source. The dynamics of such a system including accelerator physics, FEL physics, and Compton backscattering is complex and requires special study, This dissertation is a detailed theoretical and experimental analysis of such a system. The main emphasis of the theory presented here is the self-consistent analysis of the system which incorporates three drastically different processes-the dynamics of an intense electron beam, the free electron laser, and the Compton backscattering. The interdependence of these three processes and the physics of this complex system is discussed in this work. The OK-4/Duke storage ring FEL is the only accelerator facility capable of routine lasing in the deep-UV range and able to generate intense γ-ray beams with energy tunable from 2 MeV to 55 MeV, with energy resolution between 0.5%-1% and with flux up to -5 × 107. The flexibility of this γ-ray source is due to the record-breaking performance of the OK-4/Duke storage ring FEL (lasing from 193.7 nm to 730 nm). Experimental studies determining the parameters of the electron beams, OK-4 FEL beams, and γ-ray beams compare favorably with the theoretical predictions. This study confirms that the electron energy spread induced by FEL lasing is currently the main factor limiting energy resolution. These results provide a solid foundation for future development of the system to obtain more reliable predictions of its performance. A number of useful ``scaling laws'' are also presented here. The results of this work have provided the basis for a number of applications of the OK-4 FEL beam and γ- ray beam that are underway or in the advance planning stage. Future plans include the development and design of a system capable of generating γ-ray beams with an energy

  2. Users program for storage-ring based FEL and synchrotron sources of the Duke FEL Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Straub, K.D.; Barnett, G.; Burnham, B. [and others

    1995-12-31

    The storage ring at the Duke FEL Laboratory was first operated with a stored e-beam in November, 1994. It has now achieved operation energies in excess 1 GeV with more than 100 mA current at 280 MeV. The ring has several ports for FEL and synchrotron light source research. The circulating ring current can be synchronized with the seperate Mark III FEL operating in the 2-9.5 {mu}m IR region. This allows low optical jitter (10-20 ps) between the two sources and thus pump-probe operation. The ring has been configured to drive a number of light sources including the OK-4 FEL system capable of FEL operation between 400 and 65 nm, an inverse Compton scattering source using this undulator which will yield 4-200 MeV gammas, an undulator source at approximately 40 {angstrom} (not an FEL), a mm FEL with inverse compton scattering providing 1-100 keV x-rays and two synchrotron ports from the bend magnets for which the {lambda}{sub c} = 11-12 {angstrom} for 1 GeV. The broadly tunable FEL sources and their associated inverse compton scattering are extremely bright. The initial research proposals, submitted to the Laboratory emphasizes photoelectron spectroscopy, PEEM, high resolution vacuum UV of gases, solid spectroscopy and photochemistry in the UV, X-ray microprobe studies, X-ray microscopy, X-ray holography, X-ray crystallography, Mossbauer spectroscopy, nuclear spectroscopy, neutron production, photon activation therapy and broadband synchrotron as a probe of fast reaction in the IR and near IR.

  3. Multiscale degradations of storage ring FEL optics

    CERN Document Server

    Gatto, A; Amra, C; Boccara, C; Couprie, Marie Emmanuelle; De Ninno, G; Feigl, T; Garzella, D; Grewe, M; Kaiser, N; Marsi, M; Paoloni, S; Reita, V; Roger, J P; Torchio, P; Trovò, M; Walker, R; Wille, K

    2002-01-01

    The advanced understanding of the complete degradation phenomena is crucial in order to develop robust optics for FEL. Under very harsh Synchrotron Radiation conditions, results show that multiscale wavelength damages could be observed, inducing local crystalline structure modifications of the high optical index material with a severe increase of the surface roughness.

  4. PixFEL: developing a fine pitch, fast 2D X-ray imager for the next generation X-FELs

    Science.gov (United States)

    Ratti, L.; Comotti, D.; Fabris, L.; Grassi, M.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Re, V.; Traversi, G.; Vacchi, C.; Bettarini, S.; Casarosa, G.; Forti, F.; Morsani, F.; Paladino, A.; Paoloni, E.; Rizzo, G.; Benkechkache, M. A.; Dalla Betta, G.-F.; Mendicino, R.; Pancheri, L.; Verzellesi, G.; Xu, H.

    2015-10-01

    The PixFEL project is conceived as the first stage of a long term research program aiming at the development of advanced X-ray imaging instrumentation for applications at the free electron laser (FEL) facilities. The project aims at substantially advancing the state-of-the-art in the field of 2D X-ray imaging by exploring cutting-edge solutions for sensor development, for integration processes and for readout channel architectures. The main focus is on the development of the fundamental microelectronic building blocks for detector readout and on the technologies for the assembly of a multilayer module with minimum dead area. This work serves the purpose of introducing the main features of the project, together with the simulation results leading to the first prototyping run.

  5. Timing jitter studies of the SwissFEL Test Injector drive laser

    Energy Technology Data Exchange (ETDEWEB)

    Csatari Divall, Marta, E-mail: marta.divall@psi.ch [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Kaiser, Maik; Hunziker, Stephan; Vicario, Carlo; Beutner, Bolko; Schietinger, Thomas; Lüthi, Matthias; Pedrozzi, Marco [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Hauri, Christoph P. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2014-01-21

    To produce short X-ray pulses for SwissFEL, it is necessary to compress the electron bunches by a factor of 300, down to sub-fs for the attosecond operational modes. To achieve stable FEL output accurate timing of the initial electron injection at the main linear accelerator is necessary. Tolerance studies show, that to reach the final performance goals, less than 40 fs relative rms jitter is required from the electron gun, relative to the reference. Here we present independent residual RF phase noise measurements of the laser oscillators, showing an exceptional ∼30 fs integrated rms jitter. Moreover timing studies at the SwissFEL Injector Test Facility, based on charge detection at the sharp rising edge of the Schottky-scan were performed allowing for systematic correlation studies and showing a residual jitter of ∼150 fs at 10 Hz from the pulsed laser system and beam transport respect to the reference. For future development, available relative jitter measurement techniques for pulsed laser systems will be reviewed and their applicability for laser arrival time monitoring and feedback for FEL applications will be discussed.

  6. A proposed VUV oscillator-based FEL upgrade at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S. V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, D. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Evtushenko, P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hannon, F. E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hernandez-Garcia, C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Klopf, J. M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Legg, R. A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Neil, G. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Shinn, M. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, C. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Williams, G. P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2011-09-20

    Advances in superconducting linac technology offer the possibility of an upgrade of the Jefferson Lab Free Electron Laser (JLab FEL) facility to an oscillator-based VUV-FEL that would produce 6 x 10{sup 12} coherent 100 eV photons per pulse at multi-MHz repetition rates in the fundamental. At present JLab operates a pair of oscillator-based continuous-wave Free Electron Lasers (FELs) as a linac-based next generation light source in the IR and UV, with sub-picosecond pulses up to 75 MHz. Harmonics upwards of 10 eV are produced and the fully coherent nature of the source results in peak and average brightness values that are several orders of magnitude higher than storage rings. The accelerator uses an energy recovered linac design for efficiency of operation. New style superconducting linac cryomodules with higher gradient, combined with a new injector and beam transport system allow the development of the FEL to higher photon energies.

  7. Beam Property Measurements on the KU-FEL Linac

    CERN Document Server

    Masuda, Kai; Kii, Toshiteru; Murakami, Shio; Ohgaki, Hideaki; Yamazaki, Tetsuo; Yoshikawa, Kiyoshi; Zen, Heishun

    2004-01-01

    An infrared FEL facility is under construction for advanced energy researches [1]. Electron beams of around 30 MeV have been obtained by an S-band 4.5-cell rf gun with a thermionic cathode, and a recently installed 3-m accelerating tube. A 180 degree arc consisting of three bending magnets have been also set up for bunch compression, and beam property measurements are under way. Transverse phase space distributions and resultant emittances have been obtained through the tomographic technique [2] by use of a quadrupole magnet, an alumina phosphor screen and a CCD camera. An OTR screen is being prepared for a higher spatial resolution as well as for longitudinal bunch shape measurements by use of a streak camera of 0.2 psec resolution. Comparison with the start-to-end simulation results [3] will be also presented.

  8. Experimental Studies of Temporal Electron Beam Shaping at the DUV-FEL Accelerator

    CERN Document Server

    Loos, H; Doweel, D; Ferario, M; Petrarca, M; Serafini, L; Sheehy, B; Shen, Y; Tsang, Thomas; Vicario, C; Wang, X

    2005-01-01

    The photoinjectors for future short wavelength high brightness accelerator driven light sources need to produce an electron beam with ultra-low emittance. At the DUV-FEL facility at BNL, we studied the effect of longitudinally shaping the photocathode laser pulses on the electron beam dynamics. We report on measurements of transverse and longitudinal electron beam emittance and comparisons of the experimental results with simulations.

  9. Dielectric Wakefield Accelerator to drive the future FEL Light Source.

    Energy Technology Data Exchange (ETDEWEB)

    Jing, C.; Power, J.; Zholents, A. (Accelerator Systems Division (APS)); ( HEP); (LLC)

    2011-04-20

    X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

  10. Element Selective Probe of the Ultra-Fast Magnetic Response to an Element Selective Excitation in Fe-Ni Compounds Using a Two-Color FEL Source

    Directory of Open Access Journals (Sweden)

    Eugenio Ferrari

    2017-01-01

    Full Text Available The potential of the two-color mode implemented at the FERMI free-electron laser (FEL source for pumping and probing selectively different atomic species has been demonstrated by time-resolved scattering experiments with permalloy (FeNi alloy and NiFe2O4 samples. We monitored the ultra-fast demagnetization of Ni induced by the pump FEL pulse, by tuning the linearly-polarized FEL probe pulse to the Ni-3p resonance and measuring the scattered intensity in the transverse magneto-optical Kerr effect geometry. The measurements were performed by varying the intensity of the FEL pump pulse, tuning its wavelength to and off of the Fe-3p resonance, and by spanning the FEL probe pulse delays across the 300–900 fs range. The obtained results have evidenced that for the case of NiFe2O4, there is a sensible difference in the magnetic response at the Ni site when the pump pulse causes electronic excitations at the Fe site.

  11. Generation of a few femtoseconds pulses in seeded FELs using a seed laser with small transverse size

    Science.gov (United States)

    Li, Heting; Jia, Qika

    2016-09-01

    We propose a simple method to generate a few femtosecond pulses in seeded FELs. We use a longitudinal energy-chirped electron beam passing through a dogleg where transverse dispersion will generate a horizontal energy chirp, then in the modulator, a seed laser with narrow beam radius will only modulate the center portion of the electron beam and then short pulses at high harmonics will be generated in the radiator. Using a representative realistic set of parameters, we show that 30 nm XUV pulse based on the HGHG scheme and 9 nm soft x-ray pulse based on the EEHG scheme with duration of about 8 fs (FWHM) and peak power of GW level can be generated from a 180 nm UV seed laser with beam waist of 75 μm. This new scheme can provide an optional operation mode for the existing seeded FEL facilities to meet the requirement of short-pulse FEL.

  12. Growth of transverse coherence in SASE FELs

    CERN Document Server

    Kumar, V

    2000-01-01

    We introduce the correlation function between the electric field at two different points in the transverse plane as a parameter to quantify the degree of transverse coherence. We also propose a more realistic model for the initialization of the radiation in computer codes used to study SASE FELs. We make these modifications in the code TDA and use it to study the growth of transverse coherence as a function of electron beam size, beam current and transverse emittance. Our results show explicitly that the onset of full transverse coherence in SASE takes place much before the power saturates. With the more realistic model the onset of the exponential growth regime is delayed, and to get a given power from the FEL one needs a longer undulator than would be predicted by the original TDA code.

  13. Duke storage rink UV/VUV FEL: Status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.; Burnham, B.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)] [and others

    1995-12-31

    The 1 GeV Duke storage ring was successfully commissioned with parameters exceeding initial specification. The OK-4 FEL has arrived at the Duke FEL laboratory from the Novosibirsk Institute of Nuclear Physics. The OK-4 installation and commissioning is in progress. In this paper we describe the up-to-date status of the Duke storage ring and the OK-4 FEL. The projected performance of the OK-4 UV/VUV FEL is presented based on the electron beam parameters achieved. Initial plans to operate the OK-4 UV/VUV FEL at the Duke 1 GeV storage ring are outlined. Future plans and prospects of both the OK-4 FEL and the Duke storage ring are discussed.

  14. Performance of the OK-4/Duke storage ring FEL

    CERN Document Server

    Litvinenko, V N; Pinayev, I V; Wu, Y

    2001-01-01

    In this paper, we report measured parameters of the OK-4 FEL driven by the Duke storage ring. The OK-4 FEL was being operated continuously for 2 yr in the broad wavelength range for user applications utilising spontaneous and coherent XUV and UV radiation as well as Compton back-scattered gamma-rays in the range of 2-58 MeV. During this time, the OK-4 FEL lased in the range from 193.7 to about 730 nm using five sets of mirrors and electron beam energies from 240 to 800 MeV. Our predictions for the OK-4 FEL are compared with measured performance, both in the CW and in the giant pulse mode. We discuss our future plans for the OK-4 FEL operation as well as the construction and commissioning of the OK-5 FEL with helical wigglers.

  15. Characterization of X-Ray FEL Radiation

    CERN Document Server

    Bionta, R M

    2005-01-01

    The Linac Coherent Light Source (LCLS) will generate X-FEL radiation with photon energies tunable from 826 eV to 8261 eV. It is expected that elements of the Linac and Undulator systems will require careful tuning in order to achieve lasing at these wavelengths. The tuning will be guided by measurements of both the electron and photon beam characteristics. The primary characteristics of the photon beam that can be measured are the total pulse energy, its spatial shape, and spectra. During the initial commissioning phase, these measurements will be performed on the spontaneous radiation emitted by one or more undulators as they are added to the LCLS. The next phase of commissioning requires detecting and measuring faint (unsaturated) FEL radiation for the purposes of tuning the Linac and undulator to achieve saturation. During the last phases of commissioning these measurements will have to be performed on the saturated FEL beam. The photon measurements are complicated by the large dynamic range required, the ...

  16. Development of intense terahertz coherent synchrotron radiation at KU-FEL

    Science.gov (United States)

    Sei, Norihiro; Zen, Heishun; Ohgaki, Hideaki

    2016-10-01

    We produced intense coherent synchrotron radiation (CSR) in the terahertz (THz) region using an S-band linac at the Kyoto University Free Electron Laser (KU-FEL), which is a mid-infrared free-electron laser facility. The CSR beam was emitted from short-pulse electron bunches compressed by a 180° arc, and was transferred to air at a large solid angle of 0.10 rad. The measured CSR energy was 55 μJ per 7 μs macropulse, and KU-FEL was one of the most powerful CSR sources in normal conducting linear accelerator facilities. The CSR spectra were measured using an uncooled pyroelectric detector and a Michelson-type interferometer designed specifically for the KU-FEL electron beam, and had a maximum at a frequency of 0.11 THz. We found that adjusting the energy slit enhanced the CSR energy and shortened the electron beam bunch length in the CSR spectra measurements. Our results demonstrated that the efficient use of the energy slit can help improve the characteristics of CSR.

  17. The FERMI @ Elettra Technical Optimization Study: PreliminaryParameter Set and Initial Studies

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, John; Corlett, John; Doolittle, Larry; Fawley, William; Lidia, Steven; Penn, Gregory; Ratti, Alex; Staples, John; Wilcox,Russell; Wurtele, Jonathan; Zholents, Alexander

    2005-08-01

    The goal of the FERMI {at} Elettra Technical Optimization Study is to produce a machine design and layout consistent with user needs for radiation in the approximate ranges 100 nm to 40 nm, and 40 nm to 10 nm, using seeded FEL's. The Study will involve collaboration between Italian and US physicists and engineers, and will form the basis for the engineering design and the cost estimation.

  18. Preliminary Design of a Synchronized Narrow Bandwidth FEL for Taiwan Light Source

    CERN Document Server

    Keung Lau Wai; Ching Fan, Tai; Zone Hsiao Feng; Tung Hsu Kuo; Hwang, Ching Shiang; Cheng Kuo Chin; Huei Luo Guo; Jen Wang Duan; Ping Wang Jau; Huey Wang Min

    2004-01-01

    Design study of a narrow line-width, high power IR-FEL facility has been carried out at NSRRC. This machine is designed to synchronize with the U9 undulator radiation of Taiwan Light Source and therefore provide new opportunity for chemical dynamics and condensed matter research. It has been proposed to use a super-conducting linac to provide a 60 MeV high quality electron beam to drive a 2.5-10 microns FEL oscillator with U5 undulator. Operating this linac in energy recovery mode will also be considered as an option to improve overall system effeciency and reduce heat loss and radiation dosage at the beam dump. Performance requirements and outcomes from this preliminary design study will be reported.

  19. A Fast Switchyard for the TESLA FEL-Beam Using a Superconducting Transverse Mode Cavity

    CERN Document Server

    Wanzenberg, R

    2000-01-01

    In the present design of the TESLA Linear Collider with integrated X-ray Laser Facility it is necessary that 1 ms long bunch trains with about 10000 bunches are generated and distributed to several free electron laser (FEL) beam lines. The different scientific applications of the X-ray FELs need specific filling patterns of the bunches in the bunch train. It is shown that a fast switch-yard based on a superconducting transverse mode cavity can be used to generate the required bunch pattern in a flexible way while keeping the beam loading in the main linear accelerator constant. The conceptual design of the beam optics and the transverse mode cavity are presented.

  20. A hybrid type undulator for far-infrared FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Zako, A.; Miyauchi, Y.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two FEL facilities of the FELI are now operating in the wavelength range of 1-20 {mu}m. A 3.2-m hybrid type undulator ({lambda}{sub u}=80mm, N=40) has been designed for far-infrared FELs and will be installed in December. It can cover the wavelength of 20-60 {mu}m by changing K-value from 1 to 2.7 for a 28.0-MeV electron beam. It is composed of ferrite magnetic poles and Sm-Co permanent magnets. Commonly wound coils induce alternating magnetic field in ferrite poles. Combination of the induced field and the permanent magnet field can controls the magnetic field between the undulator gap.

  1. Quantum phases of Fermi-Fermi mixtures in optical lattices

    OpenAIRE

    Iskin, M.; de Melo, C. A. R. Sa

    2007-01-01

    The ground state phase diagram of Fermi-Fermi mixtures in optical lattices is analyzed as a function of interaction strength, population imbalance, filling fraction and tunneling parameters. It is shown that population imbalanced Fermi-Fermi mixtures reduce to strongly interacting Bose-Fermi mixtures in the molecular limit, in sharp contrast to homogeneous or harmonically trapped systems where the resulting Bose-Fermi mixture is weakly interacting. Furthermore, insulating phases are found in ...

  2. Wakefield issue and its impact on X-ray photon pulse in the SXFEL test facility

    CERN Document Server

    Song, Minghao; Feng, Chao; Deng, Haixiao; Liu, Bo; Wang, Dong

    2015-01-01

    Besides the designed beam acceleration, the energy of electrons changed by the longitudinal wakefields in a real free-electron laser (FEL) facility, which may degrade FEL performances from the theoretical expectation. In this paper, with the help of simulation codes, the wakefields induced beam energy loss in the sophisticated undulator section is calculated for Shanghai soft X-ray FEL, which is a two-stage seeded FEL test facility. While the 1st stage 44 nm FEL output is almost not affected by the wakefields, it is found that a beam energy loss about 0.8 MeV degrades the peak brightness of the 2nd stage 8.8 nm FEL by a factor of 1.6, which however can be compensated by a magnetic field fine tuning of each undulator segment.

  3. Observation of superradiance in a short-pulse FEL oscillator

    NARCIS (Netherlands)

    Jaroszynski, D. A.; Chaix, P.; Piovella, N.; Oepts, D.; Knippels, G.M.H.; van der Meer, A. F. G.; Weits, H. H.

    1997-01-01

    Superradiance has been experimentally studied, in a short-pulse free-electron laser (FEL) oscillator. Superradiance is the optimal way of extracting optical radiation from an FEL and can be characterised by the following scale laws: peak optical power P, scales as the square of electron charge, Q, (

  4. Fermi liquid theory

    CERN Document Server

    Apostol, M

    2001-01-01

    sup 3 He liquefies at 3.2 K under normal pressure, where its mean inter-particle separation of a few angstroms, is comparable with the range of the interaction potential (and with the mean inter-particle separation in the corresponding ideal gas); its thermal wavelength is about 8 A, so that, under this conditions, sup 3 He is a quantum liquid of fermions, or a Fermi liquid (sometimes called a normal Fermi liquid too). The motion of the sup 3 He atoms in the (repulsive) self-consistent, meanfield potential is affected by inertial effects, i.e. the particles possess an effective mass, and consequently they obey the Fermi distribution, like an ideal Fermi gas. In this paper the Landau's theory of the Fermi liquid is reviewed. (author)

  5. Feedback Requirements for SASE-FELs

    Energy Technology Data Exchange (ETDEWEB)

    Loos, Henrik; /SLAC

    2012-07-06

    The operation of a Self Amplified Spontaneous Emission (SASE) Free Electron Lasers (FEL) at soft and hard X-ray wavelengths driven by a high brightness electron beam imposes strong requirements on the stability of the accelerator and feedback systems are necessary to both guarantee saturation of the SASE process as well as a stable photon beam for user experiments. Diagnostics for the relevant transverse and longitudinal beam parameters are presented and various examples of feedback systems for bunches with low repetition rate as well as systems for intra bunch train feedbacks are discussed.

  6. Harmonic Inverse FEL Interaction at 800nm

    CERN Document Server

    Sears, C M S; Siemann, R; Spencer, J E

    2005-01-01

    The inverse Free Electron Laser (IFEL) interaction has recently been proposed and demonstrated as a premodulator for High Gain Harmonic Generation (HGHG) 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 800nm. The resonances are observed by adjusting the gap of the undulator while keeping the beam energy constant. The harmonic IFEL can add flexibility to HGHG FEL design.

  7. 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.

  8. Experimental and numerical study of short pulse effects in FELs

    CERN Document Server

    Khodyachykh, S; Genz, H; Hessler, C; Richter, A; Asgekar, V

    2004-01-01

    We report the experimental and numerical investigations of the influence of short pulse effects occurring in FELs in different operational regimes for electron bunch lengths which are of the order of the slippage distance. Several observables such as the small signal gain, the macropulse power and the spectral distribution of the FEL radiation were determined experimentally within the constraints of the stable focus regime at the infrared FEL at the S- DALINAC and for the limit cycle regime at the Dutch near infrared FEL FELIX. The experimental findings were compared to predictions of numerical simulations based on the 1D time dependent code FEL1D-OSC. The agreement between experiment and simulation is good. Furthermore, the simulations reveal a chaotic behavior of the macropulses for specific values of the slippage as well as period-doubling, two effects that are predicted to show up in the spectral distribution.

  9. Experimental and numerical study of short pulse effects in FELs

    Science.gov (United States)

    Khodyachykh, S.; Brunken, M.; Genz, H.; Hessler, C.; Richter, A.; Asgekar, V.

    2004-09-01

    We report the experimental and numerical investigations of the influence of short pulse effects occurring in FELs in different operational regimes for electron bunch lengths which are of the order of the slippage distance. Several observables such as the small signal gain, the macropulse power and the spectral distribution of the FEL radiation were determined experimentally within the constraints of the stable focus regime at the infrared FEL at the S-DALINAC and for the limit cycle regime at the Dutch near infrared FEL FELIX. The experimental findings were compared to predictions of numerical simulations based on the 1D time dependent code FEL1D-OSC. The agreement between experiment and simulation is good. Furthermore, the simulations reveal a chaotic behavior of the macropulses for specific values of the slippage as well as period-doubling, two effects that are predicted to show up in the spectral distribution.

  10. Transverse-coherence properties of the FEL at the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yuantao; Huang, Zhirong; /SLAC; Ocko, Samuel A.; /MIT, Cambridge, Dept. Phys.

    2010-09-02

    The recently commissioned Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is now operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources. Understanding of coherence properties of the radiation from SASE FELs at LCLS is of great practical importance for some user experiments. We present the numerical analysis of the coherence properties at different wavelengths based on a fast algorithmusing ideal and start-end simulated FEL fields. The sucessful commissioning and operation of the linac coherent light source (LCLS) [1] has demonstrated that the x-ray free-electron laser (FEL) has come of age; these types of x-ray sources are poised to revolutionize the ultra-fast x-ray sciences. The LCLS and other hard x-ray FELs under construction are based on the principle of self-amplified spontaneous emission (SASE) [2, 3], where the amplification process starts from the shot noise in the electron beam. A large number of transverse radiation modes are also excited when the electron beam enters the undulator. The FEL collective instability in the electron beam causes the modulation of the electron density to increase exponentially, and after sufficient undulator distances, a single transverse mode starts to dominate. As a result, SASE FEL is almost fully coherent in the transverse dimension. Understanding of transverse coherence properties of the radiation from SASE FELs is of great practical importance. The longitudinal coherence properties of SASE FELs have been studied before [4]. Some studies on the transverse coherence can be found in previous papers, for example, in ref. [5, 6, 7, 8, 9]. In this paper, we first discuss a new numerical algorithm based on Markov chain Monte Carlo techniques to calculate the FEL transverse coherence. Then we focus on the numerical analysis of the LCLS FEL transverse coherence.

  11. FTIR Spectroscopy on Basic Materials in THz Region for Compact FEL-Based Imaging

    CERN Document Server

    Cha, H J; Lee, B C; Park, S H

    2005-01-01

    We are making experiments on THz(terahertz) imaging using a compact high power FEL (free-electron laser) which is operating as a users facility at KAERI. The wavelength range of output pulses is 100~1200 μm, which corresponds to 0.3~3 THz in the frequency region. We should select the optimum wavelength for the constituents of specimens to realize the imaging based on the THz FEL. A FTIR (Fourier-transform infrared) spectrometer was modified to measure the optical constants of the specimens in THz region. A polyester film of which thickness is 3.7 μm was used as a beam splitter of the spectrometer. In the case of normal incidence, the transmittance of the film was measured to be more than 90%, and the estimated loss by absorption was approximately 2% at the FEL frequency of 3 THz. Several tens of nanometer-thick-silver was coated on the polyester film to balance both transmission and reflection of THz waves in the beam splitter. We investigated FTIR spectroscopy on air, vapor and liquid water...

  12. The SPARX Project R&D Activity towards X-rays FEL Sources

    CERN Document Server

    Alesini, David; Bertolucci, Sergio; Biagini, M E; Boni, R; Boscolo, Manuela; Castellano, Michele; Clozza, A; Di Pirro, G; Drago, A; Esposito, A; Ferrario, Massimo; Filippetto, D; Fusco, V; Gallo, A; Ghigo, A; Guiducci, Susanna; Incurvati, M; Ligi, C; Marcellini, F; Migliorati, Mauro; Mostacci, Andrea; Palumbo, Luigi; Pellegrino, L; Preger, Miro; Raimondi, Pantaleo; Ricci, R; Sanelli, C; Serio, Mario; Sgamma, F; Spataro, Bruno; Stecchi, A; Stella, A; Tazzioli, Franco; Vaccarezza, Cristina; Vescovi, Mario; Vicario, C

    2004-01-01

    SPARX is an evolutionary project proposed by a collaboration among ENEA-INFN-CNR-Università di Roma Tor Vergata aiming at the construction of a FEL-SASE X-ray source in the Tor Vergata Campus. The first phase of the SPARX project, funded by Government Agencies, will be focused on the R&D activity on critical components and techniques for future X-ray facilities. The R&D plans for the FEL source will be developped along two lines: (a) use of the SPARC high brightness photo-injector to develop experimental test on RF compression techniques and other beam physics issues, like emittance degradation in magnetic compressors due to CSR; (b) development of new undulator design concepts and up-grading of the FEL SPARC source to enhance the non linear harmonic generation mechanism, design and test of e-beam conditioning, prebunching and seeding. A parallel program will be aimed at the development of high repetition rate S-band gun, high Quantum Efficiency cathodes, high gradient X-band RF acceleratin...

  13. Characteristics Of The Duke/ok-4 Storage Ring Fel And Gamma-ray Source

    CERN Document Server

    Park, S H

    2000-01-01

    The Duke/OK-4 storage ring is a device for driving a short wavelength Free Electron Laser (FEL). In addition, Compton scattering of the laser light from the circulating electron beam products a semi-monochromatic γ-ray source. The dynamics of such a system including accelerator physics, FEL physics, and Compton backscattering is complex and requires special study, This dissertation is a detailed theoretical and experimental analysis of such a system. The main emphasis of the theory presented here is the self-consistent analysis of the system which incorporates three drastically different processes—the dynamics of an intense electron beam, the free electron laser, and the Compton backscattering. The interdependence of these three processes and the physics of this complex system is discussed in this work. The OK-4/Duke storage ring FEL is the only accelerator facility capable of routine lasing in the deep-UV range and able to generate intense γ-ray beams with energy tunable from 2 ...

  14. The GALAXIE all-optical FEL project

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, J. B.; Arab, E.; Andonian, G.; Cahill, A.; Fitzmorris, K.; Fukusawa, A.; Hoang, P.; Jovanovic, I.; Marcus, G.; Marinelli, A.; Murokh, A.; Musumeci, P.; Naranjo, B.; O' Shea, B.; O' Shea, F.; Ovodenko, A.; Pogorelsky, I.; Putterman, S.; Roberts, K.; Shumail, M. [Dept. of Physics and Astronomy, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90034 (United States); Dept. of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Dept. of Physics and Astronomy, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90034 (United States); and others

    2012-12-21

    We describe a comprehensive project, funded under the DARPA AXiS program, to develop an all-optical table-top X-ray FEL based on dielectric acceleration and electromagnetic undulators, yielding a compact source of coherent X-rays for medical and related applications. The compactness of this source demands that high field (>GV/m) acceleration and undulation-inducing fields be employed, thus giving rise to the project's acronym: GV/m AcceLerator And X-ray Integrated Experiment (GALAXIE). There are numerous physics and technical hurdles to surmount in this ambitious scenario, and the integrated solutions include: a biharmonic photonic TW structure, 200 micron wavelength electromagnetic undulators, 5 {mu}m laser development, ultra-high brightness magnetized/asymmetric emittance electron beam generation, and SASE FEL operation. We describe the overall design philosophy of the project, the innovative approaches to addressing the challenges presented by the design, and the significant progress towards realization of these approaches in the nine months since project initialization.

  15. The ARC-EN-CIEL FEL Proposal

    CERN Document Server

    Couprie, M E

    2005-01-01

    ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light), the French project of a fourth generation light source aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray. It is based on a CW 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches with a high repetition rate. The FEL is based on in the injection of High Harmonics in Gases in a High Gain Harmonic Generation scheme, leading to a rather compact solution. The produced radiation extending down to 0.8 nm with the Non Linear Harmonic reproduces the good longitudinal and transverse coherence of the harmonics in gas. Optional beam loops are foreseen to increase the beam current or the energy. They will accommodate fs synchrotron radiation sources in the IR, VUV and X ray ranges and a FEL oscillator in the 10 nm range. An important synergy is expected between accelerator and laser communities. Indeed, electron plasma accelerat...

  16. FEL gain optimisation and spontaneous radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bali, L.M.; Srivastava, A.; Pandya, T.P. [Lucknow Univ. (India)] [and others

    1995-12-31

    Colson have evaluated FEL gains for small deviations from perfect electron beam injection, with radiation of the same polarisation as that of the wiggler fields. We find that for optimum gain the polarisation of the optical field should be the same as that of the spontaneous emission under these conditions. With a helical wiggler the axial oscillations resulting from small departures from perfect electron beam injection lead to injection dependent unequal amplitudes and phases of the spontaneous radiation in the two transverse directions. Viewed along the axis therefore the spontaneous emission is elliptically polarised. The azimuth of the ellipse varies with the difference of phase of the two transverse components of spontaneous emission but the eccentricity remains the same. With planar wigglers the spontaneous emission viewed in the axial direction is linearly polarised, again with an injection dependent azimuth. For optimum coherent gain of a radiation field its polarisation characteristics must be the same as those of the spontaneous radiation with both types of wiggler. Thus, with a helical wiggler and the data reported earlier, an increase of 10% in the FEL gain at the fundamental frequency and of 11% at the fifth harmonic has been calculated in the small gain per pass limit. Larger enhancements in gain may result from more favourable values of input parameters.

  17. Fermi and Szilard

    CERN Document Server

    Byers, N

    2002-01-01

    This talk is about Enrico Fermi and Leo Szilard, their collaboration and involvement in nuclear energy development and decisions to construct and use the atomic bomb in World War II. Fermi and Szilard worked closely together at Columbia in 1939-40 to explore feasibility of a nuclear chain reaction, and then on the physics for construction of the first pile (nuclear reactor). "On matters scientific or technical there was rarely any disagreement between Fermi and myself" Szilard said. But there were sharp differences on other matters.

  18. Fermi comes to CERN

    CERN Multimedia

    NASA

    2009-01-01

    1. This view from NASA's Fermi Gamma-ray Space Telescope is the deepest and best-resolved portrait of the gamma-ray sky to date. The image shows how the sky appears at energies more than 150 million times greater than that of visible light. Among the signatures of bright pulsars and active galaxies is something familiar -- a faint path traced by the sun. (Credit: NASA/DOE/Fermi LAT Collaboration) 2. The Large Area Telescope (LAT) on Fermi detects gamma-rays through matter (electrons) and antimatter (positrons) they produce after striking layers of tungsten. (Credit: NASA/Goddard Space Flight Center Conceptual Image Lab)

  19. The Present Applications of IR FEL at Peking University

    CERN Document Server

    Yang Li Min; Zhao, Kui

    2004-01-01

    In this study the sections of human tissues were treated under 9.5 μm FEL in the BFEL based on the vibrational spectroscopic investigation that significant differences occur between normal and malignant tissues. Under the defocus condition, the burning of tissue section at some part while other part remains unchanged, suggesting that the FEL can selectively destroy some part of tissue. Vibrational spectroscopic and microscopic methods have shown that the FEL can induce decomposition of malignant tissues. The application of FEL whose wavelength is on the characteristic bands of malignant tissues may provide a new method to kill cancer cells with higher selectivity. For understanding the interactions between FEL and biological tissues, structure changes of substances under irradiation by FEL of 9.414 μm and 6.228 μm were measured using FTIR spectroscopy. The samples include ATP, ADP, AMP, and D-ribose, etc. The FTIR spectra of the molecules before and after irradiation of FEL indicate...

  20. Spontaneous emission effects in optically pumped x-ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Smetanin, I.V.; Grigor`ev, S.V. [P.N. Lebedev Physics Institute, Moscow (Russian Federation)

    1995-12-31

    An effect of spontaneous emission in both quantum and classical regimes of the optically pumped X-ray free electron laser (FEL) in investigated. The quantum properties of an FEL are determined by the ratio of the separation {h_bar} between the absorption and emission lines (i.e. the quanta emitted) and their effective width {Delta}{epsilon} {eta}={h_bar}/{Delta}{epsilon}. In the conventional classical regime {eta} {much_lt} 1 an electron emits and absorbes a great number of shortwavelength photons over the interaction region, the gain in FEL being the result of these competitive processes. In the quantum limit {eta} {much_gt} 1 the emission and absorption lines are completely separated and thus the FEL becomes a two-level quantum oscillator with a completely inverted active medium. Spontaneous emission causes the electron to leave the range of energies where resonant interaction with the laser field occurs, thus effectively reducing the number of particles that take part in generating the induced X-ray signal. This effect is found to be crucial for lasing in optically pumped X-ray FEL. The characteristic relaxation times are calculated for both classical and quantum FEL regimes. It is shown that spontaneous emission results in FEL electron beam threshold current, which is of rather high value. An optimal range of pumping laser intensities is determined.

  1. Design of a high average-power FEL driven by an existing 20 MV electrostatic-accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kimel, I.; Elias, L.R. [Univ. of Central Florida, Orlando, FL (United States)

    1995-12-31

    There are some important applications where high average-power radiation is required. Two examples are industrial machining and space power-beaming. Unfortunately, up to date no FEL has been able to show more than 10 Watts of average power. To remedy this situation we started a program geared towards the development of high average-power FELs. As a first step we are building in our CREOL laboratory, a compact FEL which will generate close to 1 kW in CW operation. As the next step we are also engaged in the design of a much higher average-power system based on a 20 MV electrostatic accelerator. This FEL will be capable of operating CW with a power output of 60 kW. The idea is to perform a high power demonstration using the existing 20 MV electrostatic accelerator at the Tandar facility in Buenos Aires. This machine has been dedicated to accelerate heavy ions for experiments and applications in nuclear and atomic physics. The necessary adaptations required to utilize the machine to accelerate electrons will be described. An important aspect of the design of the 20 MV system, is the electron beam optics through almost 30 meters of accelerating and decelerating tubes as well as the undulator. Of equal importance is a careful design of the long resonator with mirrors able to withstand high power loading with proper heat dissipation features.

  2. Fermi LAT GRBs

    Data.gov (United States)

    National Aeronautics and Space Administration — All analysis results presented here are preliminary and are not intended as an official catalog of Fermi-LAT detected GRBs. Please consult the table's caveat page...

  3. Fermi GBM Trigger Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — Fermi is a powerful space observatory that will open a wide window on the universe. Gamma rays are the highest-energy form of light, and the gamma-ray sky is...

  4. Experimental Characterization of the Seeded FEL Amplifier at the BNL SDL

    CERN Document Server

    Watanabe, T; Murphy, J B; Rose, J; Shaftan, T V; Tsang, Thomas; Wang, X J; Yu, L H

    2005-01-01

    A laser seeded near IR FEL amplifier experiment was initiated at the BNL SDL [1] to explore various schemes of FEL efficiency improvement and generation of short Rayleigh length (SRL) FEL output. The FEL achieved first SASE lasing at 0.8 μm on May 6, 2005. The experimental characterization of the laser seeded FEL output power, spectrum and transverse mode structure evolution will be presented.

  5. Beam dynamics simulations for linacs driving short-wavelength FELs

    Energy Technology Data Exchange (ETDEWEB)

    Ferrario, M.; Tazzioli, F. [Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy). Laboratori nazionali di Frascati; Serafini, L. [Milan Univ., Milan (Italy); Istituto Nazionale di Fisica Nucleare, Milan (Italy)

    1999-07-01

    The fast code HOMDYN has been recently developed, in the framework of the TTF (Tesla test facility) collaboration, in order to study the beam dynamics of linacs delivering high brightness beams as those needed for short wavelength Fel experiments. These linacs are typically driven by radio-frequency photo-injectors, where correlated time dependent space charge effects are of great relevance: these effects cannot be studied by standard beam optics codes (TRACE3D, etc.) and they have been modeled so far by means of multi-particle (Pic or quasistatic) codes requiring heavy cpu time and memory allocations. HOMDYN is able to describe the beam generation at the photo-cathode and the emittance compensation process in the injector even running on a laptop with very modest running rimes (less than a minute). In this paper it is showed how this capability of the code is exploited so to model a whole linac up to the point where the space charge dominated regime is of relevance (200 MeV).

  6. Enrico Fermi centenary exhibition seminar

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Photo 01: Dr. Juan Antonio Rubio, Leader of the Education and Technology Transfer Division and CERN Director General, Prof. Luciano Maiani. Photo 03: Luciano Maiani, Welcome and Introduction Photo 09: Antonino Zichichi, The New 'Centro Enrico Fermi' at Via Panisperna Photos 10, 13: Ugo Amaldi, Fermi at Via Panisperna and the birth of Nuclear Medicine Photo 14: Jack Steinberger, Fermi in Chicago Photo 18: Valentin Telegdi, A close-up of Fermi Photo 21: Arnaldo Stefanini, Celebrating Fermi's Centenary in Documents and Pictures.

  7. High-power FEL design issues - a critical review

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.; Madey, J.M.J.; O`Shea, P.G. [Duke Univ., Durham, NC (United States)

    1995-12-31

    The high-average power capability of FELs has been much advertised but little realized. In this paper we provide a critical analysis of the technological and economic issues associated with high-average power FEL operation from the UV to near IR. The project of IR FEL for the Siberian Center of photochemical researches is described. The distinguished features of this project are the use of the race-track microtron-recuperator and the {open_quotes}electron output of radiation{close_quotes}. The building for the machine is under reconstruction now. About half of hardware has been manufactured. The assembly of installation began.

  8. Optical Fibre Dosimeter for SASE FEL Undulators

    CERN Document Server

    Körfer, M

    2003-01-01

    Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is ...

  9. Stochastic Temporal Properties of the SASE FEL

    Energy Technology Data Exchange (ETDEWEB)

    Krinsky, S.

    2009-08-23

    We review the statistical description of the chaotic time evolution of the radiation from a self-amplified spontaneous-emission free-electron laser in the linear region before saturation. A high-gain, self-amplified spontaneous-emission (SASE) free-electron laser (FEL) [1, 2], based on modern beam technology, has the advantage of operating without a resonator and hence is capable of generating coherent radiation with wavelength down to the x-ray region. The LCLS at SLAC has recently achieved high gain and saturation at 1.5 {angstrom} [3]. A review of SASE theory can be found in ref. [4]. In this paper, we have considered the linear regime before saturation. In the nonlinear saturation regime, SASE is no longer a Gaussian process and analytic treatment is very difficult. A valuable numerical simulation analysis of the statistical behavior in the nonlinear regime can be found in ref. [10,11].

  10. An induction linac developed for FEL application

    Science.gov (United States)

    de Mascureau, J.; Anthouard, Ph.; Bardy, J.; Eyharts, Ph.; Eyl, P.; Launspach, J.; Thevenot, M.; Villate, D.

    1992-07-01

    An induction linac is being studied and built at CESTA for FEL application. At first we studied the induction technology and namely the high-voltage (HV) generators and the induction cells. A HV generator designed to feed the cells with calibrated pulses (150 kV, 50 ns, δV/V magnetic switches. This generator is planned for kHz repetition-rate operation. A prototype induction cell has also been built and tested with a cable generator. An electron injector (1.5 MeV, 1.5kA) has been designed and is now under test: it uses ten induction cells and a thermionic dispenser cathode. Numerical codes have been developed and simulations have been compared with experimental results for HV generators, induction cells, and the injector. An induction accelerating module has been studied and we plan to have the accelerator working at 3 MeV in 1992.

  11. Electro-Magnetic Quadrupole Magnets in the LCLS FEL Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Emma, P.

    2005-01-31

    We discuss various aspects of electro-magnetic quadrupole (EMQ) magnets for the LCLS FEL undulator, including their utility in beam-based alignment (BBA), magnet design issues, and impact on tunnel environment, reliability, and cost.

  12. Enrico Fermi exhibition at CERN

    CERN Document Server

    2002-01-01

    A touring exhibition celebrating the centenary of Enrico Fermi's birth in 1901 will be on display at CERN (Main Building, Mezzanine) from 12-27 September. You are cordially invited to the opening celebration on Thursday 12 September at 16:00 (Main Building, Council Chamber), which will include speechs from: Luciano Maiani Welcome and Introduction Arnaldo Stefanini Celebrating Fermi's Centenary in Documents and Pictures Antonino Zichichi The New 'Centro Enrico Fermi' at Via Panisperna Ugo Amaldi Fermi at Via Panisperna and the birth of Nuclear Medicine Jack Steinberger Fermi in Chicago Valentin Telegdi A Close-up of Fermi and the screening of a documentary video about Fermi: Scienziati a Pisa: Enrico Fermi (Scientists at Pisa: Enrico Fermi) created by Francesco Andreotti for La Limonaia from early film, photographs and sound recordings (In Italian, with English subtitles - c. 30 mins). This will be followed by an aperitif on the Mezz...

  13. Fermi comes to CERN

    CERN Multimedia

    2009-01-01

    In only 10 months of scientific activity, the Fermi space observatory has already collected an unprecedented wealth of information on some of the most amazing objects in the sky. In a recent talk at CERN, Luca Latronico, a member of the Fermi collaboration, explained some of their findings and emphasized the strong links between High Energy Physics (HEP) and High Energy Astrophysics (HEA). The Fermi gamma-ray telescope was launched by NASA in June 2008. After about two months of commissioning it started sending significant data back to the Earth. Since then, it has made observations that are changing our view of the sky: from discovering a whole new set of pulsars, the greatest total energy gamma-ray burst ever, to detecting an unexplained abundance of high-energy electrons that could be a signature of dark matter, to producing a uniquely rich and high definition sky map in gamma-rays. The high performance of the instrument comes as ...

  14. The Fermi's Bayes Theorem

    CERN Document Server

    D'Agostini, G

    2005-01-01

    It is curious to learn that Enrico Fermi knew how to base probabilistic inference on Bayes theorem, and that some influential notes on statistics for physicists stem from what the author calls elsewhere, but never in these notes, {\\it the Bayes Theorem of Fermi}. The fact is curious because the large majority of living physicists, educated in the second half of last century -- a kind of middle age in the statistical reasoning -- never heard of Bayes theorem during their studies, though they have been constantly using an intuitive reasoning quite Bayesian in spirit. This paper is based on recollections and notes by Jay Orear and on Gauss' ``Theoria motus corporum coelestium'', being the {\\it Princeps mathematicorum} remembered by Orear as source of Fermi's Bayesian reasoning.

  15. Fermi Bubbles with HAWC

    OpenAIRE

    Solares, H. A. Ayala; Hui, C. M.; Hüntemeyer, P.; collaboration, for the HAWC

    2015-01-01

    The Fermi Bubbles, which comprise two large and homogeneous regions of spectrally hard gamma-ray emission extending up to $55^{o}$ above and below the Galactic Center, were first noticed in GeV gamma-ray data from the Fermi Telescope in 2010. The mechanism or mechanisms which produce the observed hard spectrum are not understood. Although both hadronic and lep- tonic models can describe the spectrum of the bubbles, the leptonic model can also explain similar structures observed in microwave d...

  16. 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.

  17. An Overview of the MaRIE X-FEL and Electron Radiography LINAC RF Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Joseph Thomas III [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rees, Daniel Earl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scheinker, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sheffield, Richard L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-04

    The purpose of the Matter-Radiation Interactions in Extremes (MaRIE) facility at Los Alamos National Laboratory is to investigate the performance limits of materials in extreme environments. The MaRIE facility will utilize a 12 GeV linac to drive an X-ray Free-Electron Laser (FEL). Most of the same linac will also be used to perform electron radiography. The main linac is driven by two shorter linacs; one short linac optimized for X-FEL pulses and one for electron radiography. The RF systems have historically been the one of the largest single component costs of a linac. We will describe the details of the different types of RF systems required by each part of the linacs. Starting with the High Power RF system, we will present our methodology for the choice of RF system peak power and pulselength with respect to klystron parameters, modulator parameters, performance requirements and relative costs. We will also present an overview of the Low Level RF systems that are proposed for MaRIE and briefly describe their use with some proposed control schemes.

  18. Fermi Bubbles with HAWC

    CERN Document Server

    Solares, H A Ayala; Hüntemeyer, P

    2015-01-01

    The Fermi Bubbles, which comprise two large and homogeneous regions of spectrally hard gamma-ray emission extending up to $55^{o}$ above and below the Galactic Center, were first noticed in GeV gamma-ray data from the Fermi Telescope in 2010. The mechanism or mechanisms which produce the observed hard spectrum are not understood. Although both hadronic and lep- tonic models can describe the spectrum of the bubbles, the leptonic model can also explain similar structures observed in microwave data from the WMAP and Planck satellites. Recent publications show that the spectrum of the Fermi Bubbles is well described by a power law with an exponential cutoff in the energy range of 100MeV to 500GeV. Observing the Fermi Bubbles at higher gamma-ray energies will help constrain the origin of the bubbles. A steeper cutoff will favor a leptonic model. The High Altitude Water Cherenkov (HAWC) Observatory, located 4100m above sea level in Mexico, is designed to measure high-energy gamma rays between 100GeV to 100TeV. With...

  19. Optimization Issues in a Harmonic Cascade FEL

    CERN Document Server

    De Ninno, G

    2005-01-01

    Presently there is significant interest by multiple groups (e.g. BNL, ELETTRA, LBNL, BESSY, MIT) to reach short output wavelengths via a harmonic cascade FEL using an external seed laser. In a multistage device, there are a number of "free" parameters such as the nominal power of the input seed, the lengths of the individual modulator and radiator undulators, the strengths (i.e. the R56's) of the dispersive sections, the choice of the actual harmonic numbers to reach a given wavelength, etc., whose optimization is a non-trivial exercise. In particular, one can choose whether to operate predominantly in the "high gain" regime such as was proposed by Yu [1] in which case each radiator undulator is many gain lengths long or, alternatively, in the "low gain" regime in which case all undulators (except possibly the last radiator) are a couple gain lengths or less long and the output from each radiator essentially corresponds to coherent spontaneous emission from a pre-bunched beam. With particular emphasis upon th...

  20. Calibration status and plans for the charge integrating JUNGFRAU pixel detector for SwissFEL

    Science.gov (United States)

    Redford, S.; Bergamaschi, A.; Brückner, M.; Cartier, S.; Dinapoli, R.; Ekinci, Y.; Fröjdh, E.; Greiffenberg, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Rajeev, R.; Ramilli, M.; Ruder, C.; Schädler, L.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Zhang, J.

    2016-11-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector under development for photon science applications at free electron laser and synchrotron facilities. In particular, JUNGFRAU detectors will equip the Aramis end stations of SwissFEL, an X-ray free electron laser currently under construction at the Paul Scherrer Institut in Villigen, Switzerland. JUNGFRAU has been designed specifically to meet the challenges of photon science at XFELs, including high frame rates, single photon sensitivity in combination with a high dynamic range, vacuum compatibility and tilable modules. This has resulted in a charge integrating detector with three dynamically adjusting gains, a low noise of 55 ENC RMS, readout speeds in excess of 2 kHz, single photon sensitivity down to 2 keV (with a signal to noise ratio of 10) and a dynamic range covering four orders of magnitude at 12 keV. Each JUNGFRAU module consists of eight chips of 256 × 256 pixels, each 75 × 75 μm2 in size. The chips are arranged in 2 × 4 formation and bump-bonded to a single silicon sensor 320 μm thick, resulting in an active area of approximately 4 × 8 cm2 per module. Multi-module vacuum compatible systems comprising up to 16 Mpixels (32 modules) will be used at SwissFEL. The design of SwissFEL and the JUNGFRAU system for the Aramis end station A will be introduced, together with results from early prototypes and a characterisation using the first batch of final JUNGFRAU modules. Plans and first results of the pixel-by-pixel calibration will also be shown. The vacuum compatibility of the JUNGFRAU module is demonstrated for the first time.

  1. Injection system for microtron-based terehertz FEL

    Energy Technology Data Exchange (ETDEWEB)

    Kazakevich, Grigory M.; Kuznetsov, Gennady I.; Pavlov, Viatcheslav M.; /Novosibirsk, IYF; Jeong, Young Uk; Park, Seong Hee; Lee, Byung Cheol; /KAERI, Taejon

    2005-09-01

    A reliable injection system of the widely tunable microtron-based terahertz Free Electron Laser (FEL) has been developed and during last few years provides stable operation of the FEL for users. The system is based on the long-life thermionic cathode assembly using 2.5 mm-in diameter monocrystalline LaB{sub 6} emitter, heated by the tungsten cylindrical filament with the power consumption less than 55 W. The cathode emits the macro-pulse current in the range of 1-1.4 A providing operation of the terahertz FEL during more than 1000 h. The cathode assembly is installed on the cover of the I-type microtron accelerating cavity in location providing an efficient injection for the acceleration with variable number of orbits. This variation widely changes the energy of the electron beam and allows on-the-fly retuning of the FEL in the range of 1-3 THz. Pulse-signal system stabilizing the emission current prevents randomized break-downs in the accelerating cavity and decreases fluctuations of the power of the FEL radiation. The standard deviation of the fluctuations was measured to be less than 10% during long-time operation.

  2. Injection System for Microtron-Based Terahertz FEL

    CERN Document Server

    Kazakevich, G M

    2005-01-01

    A reliable injection system of the widely tunable microtron-based terahertz Free Electron Laser (FEL) has been developed and during last few years provides stable operation of the FEL for users. The system is based on the long-life thermionic cathode assembly using 2.5 mm-in diameter monocrystalline LaB6 emitter, heated by the tungsten cylindrical filament with the power consumption less than 50 W. The cathode emits the macro-pulse current in the range of 1-1.4 A providing operation of the terahertz FEL during more than 1000 h. The cathode assembly is installed on the cover of the I-type microtron accelerating cavity in location providing an efficient injection for the acceleration with variable number of orbits. This variation widely changes the energy of the electron beam and allows on-the-fly retuning of the FEL in the range of 1-3 THz. Pulse-signal system stabilizing the emission current prevents randomized break-downs in the accelerating cavity and decreases macro-pulse power fluctuations of the FEL radi...

  3. Leaky Fermi accelerators

    CERN Document Server

    Shah, Kushal; Rom-Kedar, Vered; Turaev, Dmitry

    2015-01-01

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  4. Photoinjector RF cavity design for high power CW FEL

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Young, L. M. (Lloyd M.); Schultheiss, T. (Thomas); Christina, V.; Rathke, J.

    2003-01-01

    The project is under way to develop a key enabling technology for highpower CW FEL: an RF photoinjector capable of producing continuous average current greater than 100 mA. The specific aim is a n-mode, normalconducting IW photoinjector, 3 nC of bunch charge, 100 mA of current (at 33.3-MHz bunch repetition rate) and emittance less than 10 mm-mad. This level of performance will enable robust 100-kW-class FEL operation with electron beam energy <100 MeV, thereby reducing the size and cost of the FEL. This design is scalable to the MW power level by increasing the electron bunch repetition rate to a higher value. The major challenges are emittance control and high heat flux within the CW 700-MHz RF cavities. Results of RF cavity design and cooling schemes are presented, including both high-velocity water and liquid-nitrogen cooling options.

  5. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  6. Electron Gun and Injector Designs for State-of-the-Art FELs

    CERN Document Server

    Blüm, H P; Christina, V; Cole, M D; Falletta, M; Holmes, D; Peterson, E; Rathke, J; Schultheiss, T; Todd, A M M; Wong, R

    2005-01-01

    Reliable, high-brightness, high-power injector operation is a critical technology issue for energy recovery linac drivers of high-power free electron lasers (FEL). Advanced Energy Systems is involved in three ongoing injector programs that target up to 0.5 Ampere current levels at emittance values consistent with the requirements of the FEL. One is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. A 748.5 MHz injector of this type is being assembled and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility (JLAB) beginning in 2007. The second approach being explored is a high-current normal-conducting RF photoinjector. A 700 MHz gun, presently under fabrication, will undergo thermal test in 2006 at Los Alamos National Laboratory (LANL). Finally, a half-cell 703.75 MHz SRF gun is presently being designed and will be tested to 0.5 Ampere at Brookhaven National Laboratory (BNL) in 2007. The status and projected performance for each of these injector projects is pr...

  7. Harmonic Cascade FEL Designs for LUX, a Facilty for Ultrafast X-ray Science

    CERN Document Server

    John, Corlett; Penn, Gregory; Zholents, Alexander A

    2004-01-01

    LUX is a proposed facility for ultrafast X-ray science, based on an electron beam accelerated to ~3-GeV energy in a superconducting, recirculating linac.Included in the design are multiple FEL beamlines which use the harmonic cascade approach to produce coherent XUV & soft X-ray emission beginning with a strong input external laser seed at ~200 nm wavelength. Each cascade module generally operates in the low-gain regime and is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a "virgin" pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse. For each cascade, the output photon energy can be selected over a wide range by varying the seed laser wavelength and the field strength in the undulators. We present numerical simulation results, as well as those from analytical models, to examine predicted FEL performance. We also discuss lattice considerations perti...

  8. VISA IB Ultra-High Bandwidth, High Gain SASE FEL

    CERN Document Server

    Andonian, Gerard; Murokh, Alex; Pellegrini, Claudio; Reiche, Sven; Rosenzweig, J B; Travish, Gil

    2004-01-01

    The results of a high energy-spread SASE FEL experiment, the intermediary experiment linking the VISA I and VISA II projects, are presented. A highly chirped beam (~1.7%) was transported without correction of longitudinal aberrations in the ATF dogleg, and injected into the VISA undulator. The output FEL radiation displayed an uncharacteristicly large bandwidth (~11%) with extremely stable lasing and measured energy of about 2 microJoules. Start-to-end simulations reproduce key features of the measured results and provide an insight into the mechanisms giving rise to such a high bandwidth. These analyses are described as they relate to important considerations for the VISA II experiment.

  9. Quasi-isochronous storage ring for enhanced FEL performance

    Science.gov (United States)

    Ohgaki, H.; Robin, D.; Yamazaki, T.

    1996-02-01

    A compact storage ring is designed to be used as driver for a free electron laser (FEL). This ring can be operated very close to zero momentum compaction factor (α) to increase the electron density and thus the gain of the FEL. In order to control α with zero dispersion in the straight sections we use an inverted dipole located between the bending magnets and 4 families of quadrupoles. By using 3 families of sextupoles we can control the 2 transverse chromaticities and 2nd order momentum compaction. We find that the ring has sufficient dynamic aperture for good performance.

  10. Gradient catastrophe and Fermi-edge resonances in Fermi gas.

    Science.gov (United States)

    Bettelheim, E; Kaplan, Y; Wiegmann, P

    2011-04-22

    Any smooth spatial disturbance of a degenerate Fermi gas inevitably becomes sharp. This phenomenon, called the gradient catastrophe, causes the breakdown of a Fermi sea to multiconnected components characterized by multiple Fermi points. We argue that the gradient catastrophe can be probed through a Fermi-edge singularity measurement. In the regime of the gradient catastrophe the Fermi-edge singularity problem becomes a nonequilibrium and nonstationary phenomenon. We show that the gradient catastrophe transforms the single-peaked Fermi-edge singularity of the tunneling (or absorption) spectrum to a sequence of multiple asymmetric singular resonances. An extension of the bosonic representation of the electronic operator to nonequilibrium states captures the singular behavior of the resonances.

  11. The FERMI@Elettra free-electron-laser source for coherent X-ray physics: photon properties, beam transport system, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Allaria, Enrico; Callegari, Carlo; Cocco, Daniele; Fawley, William M.; Kiskinova, Maya; Masciovecchio, Claudio; Parmigiani, Fulvio

    2010-04-05

    FERMI@Elettra is comprised of two free electron lasers (FELs) that will generate short pulses (tau ~;; 25 to 200 fs) of highly coherent radiation in the XUV and soft X-ray region. The use of external laser seeding together with a harmonic upshift scheme to obtain short wavelengths will give FERMI@Elettra the capability to produce high quality, longitudinal coherent photon pulses. This capability together with the possibilities of temporal synchronization to external lasers and control of the output photon polarization will open new experimental opportunities not possible with currently available FELs. Here we report on the predicted radiation coherence properties and important configuration details of the photon beam transport system. We discuss the several experimental stations that will be available during initial operations in 2011, and we give a scientific perspective on possible experiments that can exploit the critical parameters of this new light source.

  12. How the optical timing system,the longitudinal diagnostics and the associated feedback systems provide femtosecond stable operation at the FERMI free electron laser

    Institute of Scientific and Technical Information of China (English)

    Mario Ferianis; Enrico Allaria; Eugenio Ferrari; Giulio Gaio; Giuseppe Penco; Fabio Rossi; Marco Veronese

    2016-01-01

    FERMI, the seeded free electron laser(FEL) in operation in Italy, is providing the User Community with unique fully coherent radiation, in the wavelength range 100–4 nm. FERMI is the first FEL fully synchronized by means of optical fibers. The optical timing system ensures an ultra-stable phase reference to its distributed clients. Several femtosecond longitudinal diagnostics verify the achieved performance; the bunch length monitor(BLM) and the bunch arrival monitor(BAM) will be presented in this paper. Feedback systems play a crucial role to guarantee the needed longterm electron beam stability. A real-time infrastructure allows shot-to-shot communication between front-end computers and the servers. Orbit feedbacks are useful in machine tuning, whereas longitudinal feedbacks control electron energy,compression and arrival time. A flexible software framework allows a rapid implementation of heterogeneous multiinput–multi-output(MIMO) longitudinal loops simply by selecting the appropriate sensors and actuators.

  13. Production of transform-limited X-ray pulses through self-seeding at the European X-ray FEL

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2011-01-01

    An important goal for any advanced X-ray FEL is an option for providing Fourier-limited X-ray pulses. In this way, no monochromator is needed in the experimental hall. Self-seeding is a promising approach to significantly narrow the SASE bandwidth to produce nearly transform-limited pulses. These are important for many experiments including 3D diffraction imaging. We discuss the implementation of a single-crystal self-seeding scheme in the hard X-ray lines of the European XFEL. For this facility, transform-limited pulses are particularly valuable since they naturally support the extraction of more FEL power than at saturation by exploiting tapering in the tunable-gap baseline undulators. Tapering consists of a stepwise change of the undulator gap from segment to segment. Based on start-to-end simulations dealing with the up-to-date parameters of the European XFEL, we show that the FEL power reaches about 400 GW, or one order of magnitude higher power than the SASE saturation level (20 GW). This analysis indic...

  14. Chiral non-Fermi liquids

    Science.gov (United States)

    Sur, Shouvik; Lee, Sung-Sik

    2014-07-01

    A non-Fermi liquid state without time-reversal and parity symmetries arises when a chiral Fermi surface is coupled with a soft collective mode in two space dimensions. The full Fermi surface is described by a direct sum of chiral patch theories, which are decoupled from each other in the low-energy limit. Each patch includes low-energy excitations near a set of points on the Fermi surface with a common tangent vector. General patch theories are classified by the local shape of the Fermi surface, the dispersion of the critical boson, and the symmetry group, which form the data for distinct universality classes. We prove that a large class of chiral non-Fermi liquid states exists as stable critical states of matter. For this, we use a renormalization group scheme where low-energy excitations of the Fermi surface are interpreted as a collection of (1+1)-dimensional chiral fermions with a continuous flavor labeling the momentum along the Fermi surface. Due to chirality, the Wilsonian effective action is strictly UV finite. This allows one to extract the exact scaling exponents although the theories flow to strongly interacting field theories at low energies. In general, the low-energy effective theory of the full Fermi surface includes patch theories of more than one universality classes. As a result, physical responses include multiple universal components at low temperatures. We also point out that, in quantum field theories with extended Fermi surface, a noncommutative structure naturally emerges between a coordinate and a momentum which are orthogonal to each other. We show that the invalidity of patch description for Fermi liquid states is tied with the presence of UV/IR mixing associated with the emergent noncommutativity. On the other hand, UV/IR mixing is suppressed in non-Fermi liquid states due to UV insensitivity, and the patch description is valid.

  15. A button - type beam position monitor design for TARLA facility

    Science.gov (United States)

    Gündoǧan, M. Tural; Kaya, ć.; Yavaş, Ö.

    2016-03-01

    Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC). TARLA is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The TARLA facility is expected to provide two modes, Continuous wave (CW) and pulsed mode. Longitudinal electron bunch length will be changed between 1 and 10 ps. The bunch charge will be limited by 77pC. The design of the Button-type Beam Position Monitor for TARLA IR FEL is studied to operate in 1.3 GHz. Mechanical antenna design and simulations are completed considering electron beam parameters of TARLA. Ansoft HFSS and CST Particle Studio is used to compare with results of simulations.

  16. 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.

  17. Towards imaging of ultrafast molecular dynamics using FELs

    NARCIS (Netherlands)

    Rouzee, A.; Johnsson, P.; Rading, L.; Siu, W.; Huismans, Y.; Duesterer, S.; Redlin, H.; Tavella, F.; Stojanovic, N.; Al-Shemmary, A.; Lepine, F.; Holland, D. M. P.; Schlathölter, Thomas; Hoekstra, R.; Fukuzawa, H.; Ueda, K.; Vrakking, M. J. J.; Hundertmark, A.

    2013-01-01

    The dissociation dynamics induced by a 100 fs, 400 nm laser pulse in a rotationally cold Br-2 sample was characterized by Coulomb explosion imaging (CEI) using a time-delayed extreme ultra-violet (XUV) FEL pulse, obtained from the Free electron LASer in Hamburg (FLASH). The momentum distribution of

  18. Investigation of 3d Effects on Fel Operation

    NARCIS (Netherlands)

    van Werkhoven, G. H. C.; Faatz, B.; Schep, T. J.

    1993-01-01

    An investigation is made of 3D effects on FEL operation by comparing the 3D simulation code TDA with a 1 1/2D model. In the latter model, the full spatial dependence of the radiation field is taken into account, whereas the electrons are treated as moving in a 1D, density-averaged ponderomotive pote

  19. Application of electro-optic sampling in FEL diagnostics

    NARCIS (Netherlands)

    Yan, X.; MacLeod, A. M.; Gillespie, W. A.; Knippels, G.M.H.; Oepts, D.; van der Meer, A. F. G.

    2001-01-01

    The electro-optic sampling technique has been used for the full characterization (both amplitude and phase) of freely propagating pulsed electromagnetic radiation (such as FEL pulses, transition radiation) and for the quasistatic electric field of relativistic electron bunches. Measurements of the e

  20. Dispersion relations for 1D high-gain FELs

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-23

    We present analytical results for the one-dimensional dispersion relation for high-gain FELs. Using kappa-n distributions, we obtain analytical relations between the dispersion relations for various order kappa distributions. Since an exact solution exists for the kappa-1 (Lorentzian) distribution, this provides some insight into the number of modes on the way to the Gaussian distribution.

  1. Double-Undulator Fel for Governing by the Harmonics Generation

    NARCIS (Netherlands)

    Tulupov, A. V.

    1993-01-01

    Generation of harmonics in the double-undulator FEL based on the additional cyclotron resonance is considered. It is shown that efficient control of harmonics generation is feasible. Only one selected harmonic is generated while the others are suppressed. This effect takes place under a small value

  2. Compact THz FELs and Their Potential in Biological Applications

    CERN Document Server

    Gallerano, G P; Giovenale, E; Messina, G; Spassovsky, I P

    2005-01-01

    Two THz FEL sources are available at ENEA-Frascati covering the spectral range from 90 GHz to 0.7 THz. The first source, the ENEA Compact FEL, is based on a 5 MeV Microtron providing 4 A of peak current in 13 ps bunches. Peak power in excess of 3kW is obtained at 130 GHz. When the beam is focused, a peak E-field greater than 2 kV/cm can be obtained in the micropulse. The second source, FEL-CATS, is based on a 2.5 MeV RF Linac. After the Linac electrons enter a RF device that correlates their distribution in energy and phase. As a result a strong coherent spontaneous emission occurs in the undulator. Power up to several kW has been measured in the macropulse. The absence of a resonator results in a broad band emission from 0.4 to 0.7 THz. The peculiar temporal structure of the emitted radiation allows the investigation of the effects of high peak power, while maintaining a low average power incident on the sample. A variety of biological systems have been studied with the ENEA Compact FEL in the frame of the E...

  3. Status of the project of Novosibirsk high power FEL

    Energy Technology Data Exchange (ETDEWEB)

    Pinayev, I.V.; Erg, G.I.; Gavrilov, N.G. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)] [and others

    1995-12-31

    The project of IR FEL for the Siberian Center of photochemical researches is described. The distinguished features of this project are the use of the race-track microtron-recuperator and the {open_quotes}electron output of radiation{close_quotes}. The building for the machine is under reconstruction now. About half of hardware has been manufactured. The assembly of installation began.

  4. Berry Fermi liquid theory

    Science.gov (United States)

    Chen, Jing-Yuan; Son, Dam Thanh

    2017-02-01

    We develop an extension of the Landau Fermi liquid theory to systems of interacting fermions with non-trivial Berry curvature. We propose a kinetic equation and a constitutive relation for the electromagnetic current that together encode the linear response of such systems to external electromagnetic perturbations, to leading and next-to-leading orders in the expansion over the frequency and wave number of the perturbations. We analyze the Feynman diagrams in a large class of interacting quantum field theories and show that, after summing up all orders in perturbation theory, the current-current correlator exactly matches with the result obtained from the kinetic theory.

  5. JAERI superconducting RF linac-based free-electron laser-facility

    CERN Document Server

    Minehara, E J; Nagai, R; Kikuzawa, N; Sugimoto, M; Hajima, R; Shizuma, T; Yamauchi, T; Nishimori, N

    2000-01-01

    Recently, the JAERI superconducting RF linac based FEL has been successfully lased to produce 0.36 kW of FEL light using a 100 kW electron beam in quasi-continuous wave operation. A 1 kW class laser is our present program goal, and will be achieved by improving the optical out coupling in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. Our next 5-year program goal is to produce a 100 kW-class FEL laser and multi-MW class electron beam in average, quasi-continuous wave operation. Conceptual and engineering design options needed for such a very high-power operation will be discussed to improve and to upgrade the existing facility.

  6. New physics of metals: fermi surfaces without Fermi liquids.

    OpenAIRE

    Anderson, P W

    1995-01-01

    I relate the historic successes, and present difficulties, of the renormalized quasiparticle theory of metals ("AGD" or Fermi liquid theory). I then describe the best-understood example of a non-Fermi liquid, the normal metallic state of the cuprate superconductors.

  7. Attachment of Surface "Fermi Arcs" to the Bulk Fermi Surface: "Fermi-Level Plumbing" in Topological Metals

    OpenAIRE

    Haldane, F. D. M.

    2014-01-01

    The role of "Fermi arc" surface-quasiparticle states in "topological metals" (where some Fermi surface sheets have non-zero Chern number) is examined. They act as "Fermi-level plumbing" conduits that transfer quasiparticles among groups of apparently-disconnected Fermi sheets with non-zero Chern numbers to maintain equality of their chemical potentials, which is required by gauge invariance. Fermi arcs have a chiral tangential attachment to the surface projections of sheets of the bulk Fermi ...

  8. 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.

  9. Fermi Communications and Public Outreach

    CERN Document Server

    Cominsky, L

    2015-01-01

    The Sonoma State University (SSU) Education and Public Outreach (E/PO) group participates in the planning and execution of press conferences that feature noteworthy Fermi discoveries, as well as supporting social media and outreach websites. We have also created many scientific illustrations for the media, tools for amateur astronomers for use at star parties, and have given numerous public talks about Fermi discoveries.

  10. FERMI multi-chip module

    CERN Multimedia

    This FERMI multi-chip module contains five million transistors. 25 000 of these modules will handle the flood of information through parts of the ATLAS and CMS detectors at the LHC. To select interesting events for recording, crucial decisions are taken before the data leaves the detector. FERMI modules are being developed at CERN in partnership with European industry.

  11. Enrico Fermi Symposium at CERN : opening celebration

    CERN Document Server

    CERN. Geneva. Audiovisual Unit

    2002-01-01

    You are cordially invited to the opening celebration on Thursday 12 September at 16:00 (Main Building, Council Chamber), which will include speechs from: Luciano Maiani - Welcome and Introduction Antonino Zichichi - The New 'Centro Enrico Fermi' at Via Panisperna Ugo Amaldi - Fermi at Via Panisperna and the birth of Nuclear Medicine Jack Steinberger - Fermi in Chicago Valentin Telegdi - A Close-up of Fermi Arnaldo Stefanini - Celebrating Fermi's Centenary in Documents and Pictures and the screening of a documentary video about Fermi: Scienziati a Pisa: Enrico Fermi (Scientists at Pisa: Enrico Fermi) created by Francesco Andreotti for La Limonaia from early film, photographs and sound recordings (English version - c. 30 mins).

  12. Fermi, Heisenberg y Lawrence

    Directory of Open Access Journals (Sweden)

    Ynduráin, Francisco J.

    2002-01-01

    Full Text Available Not available

    Los azares de las onomásticas hacen coincidir en este año el centenario del nacimiento de tres de los más grandes físicos del siglo XX. Dos de ellos, Fermi y Heisenberg, dejaron una marca fundamental en la ciencia (ambos, pero sobre todo el segundo y, el primero, también en la tecnología. Lawrence, indudablemente de un nivel inferior al de los otros dos, estuvo sin embargo en el origen de uno de los desarrollos tecnológicos que han sido básicos para la exploración del universo subnuclear en la segunda mitad del siglo que ha terminado hace poco, el de los aceleradores de partículas.

  13. Field Encapsulation Library The FEL 2.2 User Guide

    Science.gov (United States)

    Moran, Patrick J.; Henze, Chris; Ellsworth, David

    1999-01-01

    This document describes version 2.2 of the Field Encapsulation Library (FEL), a library of mesh and field classes. FEL is a library for programmers - it is a "building block" enabling the rapid development of applications by a user. Since FEL is a library intended for code development, it is essential that enough technical detail be provided so that one can make full use of the code. Providing such detail requires some assumptions with respect to the reader's familiarity with the library implementation language, C++, particularly C++ with templates. We have done our best to make the explanations accessible to those who may not be completely C++ literate. Nevertheless, familiarity with the language will certainly help one's understanding of how and why things work the way they do. One consolation is that the level of understanding essential for using the library is significantly less than the level that one should have in order to modify or extend the library. One more remark on C++ templates: Templates have been a source of both joy and frustration for us. The frustration stems from the lack of mature or complete implementations that one has to work with. Template problems rear their ugly head particularly when porting. When porting C code, successfully compiling to a set of object files typically means that one is almost done. With templated C++ and the current state of the compilers and linkers, generating the object files is often only the beginning of the fun. On the other hand, templates are quite powerful. Used judiciously, templates enable more succinct designs and more efficient code. Templates also help with code maintenance. Designers can avoid creating objects that are the same in many respects, but not exactly the same. For example, FEL fields are templated by node type, thus the code for scalar fields and vector fields is shared. Furthermore, node type templating allows the library user to instantiate fields with data types not provided by the FEL

  14. Wakefield issue and its impact on X-ray photon pulse in the SXFEL test facility

    Science.gov (United States)

    Song, Minghao; Li, Kai; Feng, Chao; Deng, Haixiao; Liu, Bo; Wang, Dong

    2016-06-01

    Besides the designed beam acceleration, the energy of electrons is changed by the longitudinal wakefields in a real free-electron laser (FEL) facility, which may degrade FEL performances from the theoretical expectation. In this paper, with the help of simulation codes, the wakefields induced beam energy loss in the sophisticated undulator section is calculated for Shanghai soft X-ray FEL, which is a two-stage seeded FEL test facility. While the 1st stage 44 nm FEL output is almost not affected by the wakefields, it is found that a beam energy loss about 0.8 MeV degrades the peak brightness of the 2nd stage 8.8 nm FEL by a factor of 1.6, which however can be compensated by a magnetic field fine tuning of each undulator segment. And the longitudinal coherence of the 8.8 nm FEL output illustrates a slight degradation, because of the beam energy curvatures induced by the wakefields.

  15. Anisotropic non-Fermi liquids

    Science.gov (United States)

    Sur, Shouvik; Lee, Sung-Sik

    2016-11-01

    We study non-Fermi-liquid states that arise at the quantum critical points associated with the spin density wave (SDW) and charge density wave (CDW) transitions in metals with twofold rotational symmetry. We use the dimensional regularization scheme, where a one-dimensional Fermi surface is embedded in (3 -ɛ ) -dimensional momentum space. In three dimensions, quasilocal marginal Fermi liquids arise both at the SDW and CDW critical points: the speed of the collective mode along the ordering wave vector is logarithmically renormalized to zero compared to that of Fermi velocity. Below three dimensions, however, the SDW and CDW critical points exhibit drastically different behaviors. At the SDW critical point, a stable anisotropic non-Fermi-liquid state is realized for small ɛ , where not only time but also different spatial coordinates develop distinct anomalous dimensions. The non-Fermi liquid exhibits an emergent algebraic nesting as the patches of Fermi surface are deformed into a universal power-law shape near the hot spots. Due to the anisotropic scaling, the energy of incoherent spin fluctuations disperse with different power laws in different momentum directions. At the CDW critical point, on the other hand, the perturbative expansion breaks down immediately below three dimensions as the interaction renormalizes the speed of charge fluctuations to zero within a finite renormalization group scale through a two-loop effect. The difference originates from the fact that the vertex correction antiscreens the coupling at the SDW critical point whereas it screens at the CDW critical point.

  16. The Infrared Undulator Project at the VUV-FEL

    CERN Document Server

    Grimm, O; Rossbach, J; Saldin, E L; Schneidmiller, E; Yurkov, M V

    2005-01-01

    A special electromagnetic wiggler generating infrared radiation in the range 1-200 microns is planned to be installed at the DESY VUV-FEL in Hamburg by autumn 2006. The device is located after the FEL undulators, using the spent electron beam. The purpose is two-fold: first, it will serve longitudinal electron beam diagnostics, similar to other methods currently investigated using the coherent emission of radiation at wavelengths similar to the bunch length, and second it will be used as a powerful (100 MW peak) source for short (few ps) infrared radiation pulses. The natural, perfect synchronization with the VUV pulses will allow for pump-probe experiments with high timing precision. This paper will give an overview of the project, including the infrared beam transport line.

  17. Ultrafast Coherent Control and Characterization of Surface Reactions using FELs

    CERN Document Server

    Ogasawara, Hirohito; Nordlund, Dennis

    2005-01-01

    The microscopic understanding of surface chemistry requires a detailed understanding of the dynamics of elementary processes at surfaces. The ultrashort electron pulse obtained in the linear accelerator to feed the FEL can be used for generation of coherent synchrotron radiation in the low energy THz regime. With the current parameters for LCLS this corresponds to radiation with energy corresponding to excitations of low-energy vibrational modes of molecules on surfaces or phonons in substrates. The coherent radiation can coherently manipulate atoms or molecules on surfaces. In this respect a chemical reaction can be initiated by coherent atomic motion along a specific reaction coordinate. Since the THz radiation is generated from the same source as the FEL radiation full-time synchronization for pump-probe experiments will be possible. The possibility to perform time-resolved X-ray Emission Spectroscopy (XES) and X-ray Photoelectron Spectroscopy (XPS) measurements as a probe of chemical dynamics is an exciti...

  18. Feedback Control Of Dynamical Instabilities In Classical Lasers And Fels

    CERN Document Server

    Bielawski, S; Szwaj, C

    2005-01-01

    Dynamical instabilities lead to unwanted full-scale power oscillations in many classical lasers and FEL oscillators. For a long time, applications requiring stable operation were typically performed by working outside the problematic parameter regions. A breakthrough occurred in the nineties [1], when emphasis was made on the practical importance of unstable states (stationary or periodic) that coexist with unwanted oscillatory states. Indeed, although not observable in usual experiments, unstable states can be stabilized, using a feedback control involving arbitrarily small perturbations of a parameter. This observation stimulated a set of works leading to successful suppression of dynamical instabilities (initially chaos) in lasers, sometimes with surprisingly simple feedback devices [2]. We will review a set of key results, including in particular the recent works on the stabilization of mode-locked lasers, and of the super-ACO, ELETTRA and UVSOR FELs [3].

  19. Accelerating Rf System Of Microtron-recuperator For Fel

    CERN Document Server

    Arbuzov, V S; Gorniker, E I; Kendjebulatov, E K; Kolobanov, E I; Kondakov, A A; Krutikhin, S A; Kuptsov, I V; Kurkin, G Ya; Medvedev, L E; Motygin, S V; Osipov, V N; Petrov, V M; Pilan, Andrey M; Popov, A M; Sedlyarov, I K; Tribendis, A G

    2004-01-01

    FEL (Free Electron Laser) for the Siberian Centre of Photochemical Research is constructed in Novosibirsk. Parameters and last results received on a RF system of the race-track microtron-recuperator for FEL are given in the report. The frequency of the RF system is 180.4 MHz. The RF system operates in continuous mode. The 16 cavities are used in accelerating system of the microtron-recuperator. The RF system is consists of two channels. Each of two 600kW generators drives 8 cavities. Each channel was tested at 7500 kV on the gaps of 8 cavities. The RF power was 630 kW per channel. Now, the accelerating RF system operates at 13600 kV on 16 cavities. Total power of generators is 1100kW.

  20. First lasing of the IR upgrade FEL at Jefferson lab

    Energy Technology Data Exchange (ETDEWEB)

    Christopher Behre; Stephen Benson; George Biallas; James Boyce; Christopher Curtis; David Douglas; H. Dylla; L. Dillon-townes; Richard Evans; Albert Grippo; Joseph Gubeli; David Hardy; John Heckman; Carlos Hernandez-Garcia; Tommy Hiatt; Kevin Jordan; Nikolitsa Merminga; George Neil; Joseph Preble; Harvey Rutt; Michelle D. Shinn; Timothy Siggins; Hiroyuki Toyokawa; David W. Waldman; Richard Walker; Neil Wilson; Byung Yunn; Shukui Zhang

    2004-08-01

    We report initial lasing results from the IR Upgrade FEL at Jefferson Lab[1]. The electron accelerator was operated with low average current beam at 80 MeV. The time structure of the beam was 120 pC bunches at 4.678 MHz with up to 750 {micro}sec pulses at 2Hz. Lasing was established over the entire wavelength range of the mirrors (5.5-6.6 {micro}m). The detuning curve length, turn-on time, and power were in agreement with modeling results assuming a 1 psec FWHM micropulse. The same model predicts over 10 kW of power output with 10 mA of beam and 10% output coupling, which is the ultimate design goal of the IR Upgrade FEL. The behavior of the laser while the dispersion section strength was varied was found to qualitatively match predictions. Initial CW lasing results also will be presented.

  1. Terahertz IFEL/FEL Microbunching for Plasma Beatwave Accelerators

    CERN Document Server

    Sung, Chieh; Joshi, Chandrashekhar; Musumeci, Pietro; Pellegrini, Claudio; Ralph, Joseph; Reiche, Sven; Rosenzweig, James E; Tochitsky, Sergei Ya

    2005-01-01

    In order to obtain monoenergetic acceleration of electrons, phase-locked injection using electron microbunches shorter than the accelerating structure is necessary. For a laser-driven plasma beatwave accelerator experiment, we propose to microbunch the electrons by interaction with terahertz (THz) radiation in an undulator via two mechanisms– free electron laser (FEL) and inverse free electron laser (IFEL). Since the high power FIR radiation will be generated via difference frequency mixing in GaAs by the same CO2 beatwave used to drive the plasma wave, electrons could be phase-locked and pre-bunched into a series of microbunches separated with the same periodicity. Here we examine the criteria for undulator design and present simulation results for both IFEL and FEL approaches. Using different CO2 laser lines, electrons can be microbunched with different periodicity 300 – 100 mm suitable for injection into plasma densities in the range 1016 – 1017 cm-3, respectively. The requiremen...

  2. Cavity-mirror degradation in the deep-UV FEL

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, K.; Yamazaki, T.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    It is known that the degradation of dielectric multilayer mirrors used in short wavelength free-electron lasers (FELs) is caused by the carbon contamination on the mirror surface and the defects inside the dielectrics. We reported last year that the degraded dielectric multilayer mirrors can be repaired with both surface treatment by RF-induced oxygen plasma and thermal annealing. However, such a mirror degradation is still one of the most critical issues in the deep ultraviolet (UV) FELs, because the fundamental undulator radiation resonating in the laser cavity, the intensity of which is much higher than that of higher harmonics, can be sufficiently energetic to cause the mirror degradation through photochemical reactions. We are investigating the mirror degradation mainly in the deep UV region down to 240 nm. The experimental results will be shown. The mirror degradation mechanism will be discussed.

  3. A wiggler magnet for FEL low voltage operation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Shamma`a, A.; Stuart, R.A.; Lucas, J.

    1995-12-31

    In low voltage FELs (ie, 200kV), operation is necessarily in the microwave frequency range for wiggler periods of the order of cms., so that a waveguide system is mandatory. Also, because of the relatively low velocity of the electron beam, the wiggle amplitude of the electron beam can be much larger than is normal for highly relativistic FELs. Both these factors mean that the electron trajectory must be carefully controlled to avoid beam collision with the waveguide walls. A wiggler system with half poles at entrance and exit is not an acceptable solution because of the offset is gives rise to the electron trajectory. Consequently, we have designed and constructed a wiggler magnet with exponential entrance and exit tapers for a minimal deflection and displacement of the electron beam. Simulations and experimental measurements showed that an on axis trajectory is easily obtainable.

  4. Possible enhancement of SASE FEL output field intensity induced by local phase jump

    Science.gov (United States)

    Varfolomeev, A. A.; Yarovoi, T. V.; Bousine, P. V.

    1998-02-01

    A possible influence on the FEL dynamics of a locally induced phase jump between the FEL radiation and electron beam is considered. A numerical study has been made for the SASE mode FEL supposing that the phase jumps are introduced at different depths inside the undulator. The FEL evolution starting from a small input signal was studied in 1D high gain approach. It was shown that the FEL radiation output is sensitive to the phase jump value if it is introduced at the depth where saturation of output power takes places. In the steady state regime, the phase displacement of order ˜π provides enhancement of the peak output power up to 50%. Some kind of optical tapering is also possible giving further FEL efficiency enhancement.

  5. Macro-particle FEL model with self-consistent spontaneous radiation

    CERN Document Server

    Litvinenko, Vladimir N

    2015-01-01

    Spontaneous radiation plays an important role in SASE FELs and storage ring FELs operating in giant pulse mode. It defines the correlation function of the FEL radiation as well as its many spectral features. Simulations of these systems using randomly distributed macro-particles with charge much higher that of a single electron create the problem of anomalously strong spontaneous radiation, limiting the capabilities of many FEL codes. In this paper we present a self-consistent macro-particle model which provided statistically exact simulation of multi-mode, multi-harmonic and multi-frequency short-wavelength 3-D FELs including the high power and saturation effects. The use of macro-particle clones allows both spontaneous and induced radiation to be treated in the same fashion. Simulations using this model do not require a seed and provide complete temporal and spatial structure of the FEL optical field.

  6. Photoinjector RF cavity design for high power CW FEL

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Young, L. M. (Lloyd M.); Schultheiss, T. (Thomas); Christina, V.; Rathke, J. (John)

    2002-01-01

    The project is under way to develop a key enabling technology for high-power CW FEL: an RF photoinjector capable of producing continuous average current greater than 100 mA. The specific aim is a 700 MHz pi-mode, normal-conducting RF photoinjector, 3 nC of bunch charge, 100 mA of current (at 33.3-MHz bunch repetition rate) and emittance less than 10 mm-mrad. This level of performance will enable robust 100-kW-class FEL operation with electron beam energy 400 MeV, thereby reducing the size and cost of the FEL. This design is scalable to the MW power level by increasing the electron bunch repetition rate from 33.3 MHz to a higher value. The major challenges are emittance control and high heat flux within the CW 700-MHz RF cavities. Results of RF cavity design and cooling schemes are presented, including both high-velocity water and liquid nitrogen cooling options.

  7. An advanced UV optical cavity for the European FEL project

    CERN Document Server

    Poole, M W; Chesworth, A A; Clarke, J A; Fell, B; Hill, C; Marl, R; Mullacrane, I D; Reid, R J

    2000-01-01

    A European collaboration is constructing a short wavelength FEL for the ELETTRA storage ring. The optical cavity has been designed and constructed at Daresbury Laboratory for delivery to Sincrotrone Trieste in Autumn 1999, following commissioning tests over the Summer. Initial FEL operation will be at 350 nm but subsequently down to 200 nm or less and mirrors will be 40 mm diameter. The 32 m optical cavity is controllable to 0.01 mu rad in mirror pitch and yaw using digital piezo translators. A novel feature is the simultaneous presence of three remotely interchangeable mirrors to extend the tuning range and also to interchange damaged mirrors immediately. In addition, a transfer arm and load-lock arrangement will permit a mirror to be withdrawn from the chamber and replaced without disruption to the UHV system. The FEL is designed to operate at high power (1-10 W) and multi-watt spontaneous emission is also present: power loading has been investigated by FEA analysis and has necessitated specification of a w...

  8. Electron bunch length measurement at the Vanderbilt FEL

    Energy Technology Data Exchange (ETDEWEB)

    Amirmadhi, F.; Brau, C.A.; Mendenhall, M. [Vanderbilt Free-Electron-Laser Center, Nashville, TN (United States)] [and others

    1995-12-31

    During the past few years, a number of experiments have been performed to demonstrate the possibility to extract the longitudinal charge distribution from spectroscopic measurements of the coherent far-infrared radiation emitted as transition radiation or synchrotron radiation. Coherent emission occurs in a spectral region where the wavelength is comparable to or longer than the bunch length, leading to an enhancement of the radiation intensity that is on the order of the number of particles per bunch, as compared to incoherent radiation. This technique is particularly useful in the region of mm and sub-mm bunch lengths, a range where streak-cameras cannot be used for beam diagnostics due to their limited time resolution. Here we report on experiments that go beyond the proof of principle of this technique by applying it to the study and optimization of FEL performance. We investigated the longitudinal bunch length of the Vanderbilt FEL by analyzing the spectrum of coherent transition radiation emitted by the electron bunches. By monitoring the bunch length while applying a bunch-compression technique, the amount of the compression could be easily observed. This enabled us to perform a systematic study of the FEL performance, especially gain and optical pulse width, as a function of the longitudinal electron distribution in the bunch. The results of this study will be presented and discussed.

  9. The fermi paradox is neither Fermi's nor a paradox.

    Science.gov (United States)

    Gray, Robert H

    2015-03-01

    The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth--and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked "Where is everybody?"--apparently suggesting that we do not see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist or suggesting its absence is paradoxical. The claim "they are not here; therefore they do not exist" was first published by Michael Hart, claiming that interstellar travel and colonization of the Galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important, because the Fermi paradox is seen by some as an authoritative objection to searching for evidence of extraterrestrial intelligence--cited in the U.S. Congress as a reason for killing NASA's SETI program on one occasion. But evidence indicates that it misrepresents Fermi's views, misappropriates his authority, deprives the actual authors of credit, and is not a valid paradox.

  10. Thin-film deposition method assisted by mid-infrared-FEL

    CERN Document Server

    Yasumoto, M; Ishizu, A; Tsubouchi, N; Awazu, K; Umesaki, N

    2001-01-01

    We propose the novel application of the mid-infrared (MIR) FEL to the thin-film fabrication process. During the application, a substrate on which a thin film is being fabricated by a conventional method is simultaneously irradiated by the MIR FEL. The MIR FEL induces the fabricated molecules into the excited state of the stretching vibration energy, when the photon energy of the MIR FEL corresponds to one of the molecules. Therefore, the method can assist the thin-film fabrication quasi-independent of the substrate temperature. The method has the advantages of application on a temperature sensitive substrate and selective fabrication due to the tunable wavelength of the MIR FEL. In order to realize the method, we developed two thin film fabrication devices; an MIR FEL assisted RF sputtering device and an MIR FEL assisted laser ablation deposition device. For the method, the intensity of the assisted MIR FEL is an important problem. Thus the cross-section of the MIR FEL intensity profile is shown and the propa...

  11. Enrico Fermi the obedient genius

    CERN Document Server

    Bruzzaniti, Giuseppe

    2016-01-01

    This biography explores the life and career of the Italian physicist Enrico Fermi, which is also the story of thirty years that transformed physics and forever changed our understanding of matter and the universe: nuclear physics and elementary particle physics were born, nuclear fission was discovered, the Manhattan Project was developed, the atomic bombs were dropped, and the era of “big science” began. It would be impossible to capture the full essence of this revolutionary period without first understanding Fermi, without whom it would not have been possible. Enrico Fermi: The Obedient Genius attempts to shed light on all aspects of Fermi’s life - his work, motivation, influences, achievements, and personal thoughts - beginning with the publication of his first paper in 1921 through his death in 1954. During this time, Fermi demonstrated that he was indeed following in the footsteps of Galileo, excelling in his work both theoretically and experimentally by deepening our understanding of the Pauli e...

  12. Fermi pulsar revolution

    CERN Document Server

    Caraveo, Patrizia A

    2010-01-01

    2009 has been an extraordinary year for gamma-ray pulsar astronomy and 2010 promises to be equally good. Not only have we registered an extraordinary increase in the number of pulsars detected in gamma rays, but we have also witnessed the birth of new sub-families: first of all, the radio-quiet gamma pulsars and later an ever growing number of millisecond pulsars, a real surprise. We started with a sample of 7 gamma-ray emitting neutron stars (6 radio pulsars and Geminga) and now the Fermi-LAT harvest encompasses 24 "Geminga-like" new gamma-ray pulsars, a dozen millisecond pulsars and about thirty radio pulsars. Moreover, radio searches targeted to LAT unidentified sources yielded 18 new radio millisecond pulsars, several of which have been already detected also in gamma rays. Thus, currently the family of gamma-ray emitting neutron stars seems to be evenly divided between classical radio pulsars, millisecond pulsars and radio quiet neutron stars.

  13. 75 FR 63867 - DTE Energy; Enrico Fermi Atomic Power Plant Unit 1, Exemption From Certain Security Requirements

    Science.gov (United States)

    2010-10-18

    .... Nuclear Regulatory Commission (NRC or the Commission) now or hereafter in effect. Fermi 1 was a fast breeder reactor power plant cooled by sodium and operated at essentially atmospheric pressure. In November... in Monroe County, Michigan. Fermi 1 is a permanently shutdown nuclear reactor facility. The...

  14. Production of transform-limited X-ray pulses through self-seeding at the European X-ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-09-15

    An important goal for any advanced X-ray FEL is an option for providing Fourier-limited X-ray pulses. In this way, no monochromator is needed in the experimental hall. Self-seeding is a promising approach to significantly narrow the SASE bandwidth to produce nearly transform-limited pulses. These are important for many experiments including 3D diffraction imaging.We discuss the implementation of a single-crystal self-seeding scheme in the hard X-ray lines of the European XFEL. For this facility, transform-limited pulses are particularly valuable since they naturally support the extraction of more FEL power than at saturation by exploiting tapering in the tunable-gap baseline undulators. Tapering consists of a stepwise change of the undulator gap from segment to segment. Based on start-to-end simulations dealing with the up-to-date parameters of the European XFEL, we show that the FEL power reaches about 400 GW, or one order of magnitude higher power than the SASE saturation level (20 GW). This analysis indicates that our self-seeding scheme is not significantly affected by non-ideal electron phase-space distribution, and yields about the same performance as in the case for an electron beam with ideal parameters. The self-seeding scheme with a single crystal monochromator is extremely compact (about 5 m long), and cost estimations are low enough to consider adding it to the European XFEL capabilities from the very beginning of the operation phase. (orig.)

  15. Status of the SXFEL Facility

    Directory of Open Access Journals (Sweden)

    Zhentang Zhao

    2017-06-01

    Full Text Available The Shanghai soft X-ray Free-Electron Laser facility (SXFEL is being developed in two steps; the SXFEL test facility (SXFEL-TF, and the SXFEL user facility (SXFEL-UF. The SXFEL-TF is a critical development step towards the construction a soft X-ray FEL user facility in China, and is under commissioning at the Shanghai Synchrotron Radiation Facility (SSRF campus. The test facility is going to generate 8.8 nm FEL radiation using an 840 MeV electron linac passing through the two-stage cascaded HGHG-HGHG or EEHG-HGHG (high-gain harmonic generation, echo-enabled harmonic generation scheme. The construction of the SXFEL-TF started at the end of 2014. Its accelerator tunnel and klystron gallery were ready for equipment installation in April 2016, and the installation of the SXFEL-TF linac and radiator undulators were completed by the end of 2016. In the meantime, the SXFEL-UF, with a designated wavelength in the water window region, began construction in November 2016. This was based on upgrading the linac energy to 1.5 GeV, and the building of a second undulator line and five experimental end-stations. Construction status and the future plans of the SXFEL are reported in this paper.

  16. Step-tapered operation of the FEL: Efficiency enhancement and two-colour operation

    NARCIS (Netherlands)

    Jaroszynski, D. A.; Prazeres, R.; Glotin, F.; Marcouille, O.; Ortega, J. M.; Oepts, D.; van der Meer, A. F. G.; Knippels, G.M.H.; van Amersfoort, P. W.

    1996-01-01

    We present measurements of the temporal and spectral properties of radiation produced from the step-tapered undulator infrared free-electron lasers (FELs), CLIO in France and FELIX in the Netherlands. Using a two section undulator with independently adjustable deflection parameters, K, the FEL will

  17. Coherent undulator radiation of electron beam, microbunched for the FEL power outcoupling

    Energy Technology Data Exchange (ETDEWEB)

    Kulipanov, G.N.; Sokolov, A.S.; Vinokurov, N.A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1995-12-31

    The spectral intensity of the coherent undulator radiation of electron beam, preliminarily microbunched by the FEL oscillator for the FEL power outcoupling, is approximately calculated by simple analytic considerations, taking into account the transverse emittances and the energy spread of the microbunched electron beams.

  18. Real time diagnostic for operation at a CW low voltage FEL

    Energy Technology Data Exchange (ETDEWEB)

    Balfour, C.; Shaw, A.; Mayhew, S.E. [and others

    1995-12-31

    At Liverpool University, a system for single user control of an FEL has been designed to satisfy the low voltage FEL (ie 200kV) operational requirements. This system incorporates many aspects of computer automation for beam diagnostics, radiation detection and vacuum system management. In this paper the results of the development of safety critical control systems critical control systems are reported.

  19. Wavelength dependent delay in the onset of FEL tissue ablation

    Energy Technology Data Exchange (ETDEWEB)

    Tribble, J.A.; Edwards, G.S. [Vanderbilt Univ., Nashville, TN (United States); Lamb, J.A. [Massachusetts General Hospital, Boston, MA (United States)] [and others

    1995-12-31

    We are investigating the wavelength dependence of the onset of laser tissue ablation in the IR Visible and UV ranges. Toward this end, we have made simultaneous measurements of the ejected material (using a HeNe probe beam tangential to the front surface) and the residual stress transient in the tissue (using traditional piezoelectric detection behind the thin samples). For the IR studies we have used the Vanderbilt FEL and for the UV and Vis range we have used a Q-switched ND:Yag with frequency doubling and quadrupling. To satisfy the conditions of the near field limit for the detection of the stress transient, the duration of the IR FEL macropulse must be as short as possible. We have obtained macropulses as short as 100 ns using Pockels Cell technology. The recording of the signals from both the photodiode monitoring the HeNe probe beam and the acoustic detector are synchronized with the arrival of the 100 ns macropulse. With subablative intensities, the resulting stress transient is bipolar with its positive peak separated from its negative peak by 100 ns in agreement with theory. Of particular interest is the comparison of ablative results using 3 {mu}m and 6.45 {mu}m pulses. Both the stress transient and the ejection of material suffer a greater delay (with respect to the arrival of the 100 ns pulse) when the FEL is tuned to 3 {mu}m as compared to 6.45 {mu}m. A comparison of IR Vis and UV data will be discussed in terms of microscopic mechanisms governing the laser ablation process.

  20. Single spike operation in SPARC SASE-FEL

    Energy Technology Data Exchange (ETDEWEB)

    Boscolo, M. [INFN/LNF, Via Enrico Fermi 40, 00044 Frascati, Roma (Italy)], E-mail: Manuela.Boscolo@lnf.infn.it; Ferrario, M. [INFN/LNF, Via Enrico Fermi 40, 00044 Frascati, Roma (Italy); Boscolo, I.; Castelli, F.; Cialdi, S.; Petrillo, V. [University of Milano, Via Celoria 16, 20133 Milano (Italy); Bonifacio, R. [CBPF, Rio de Janeiro (Brazil); Palumbo, L. [La Sapienza, Roma (Italy); Serafini, L. [INFN/MI, Via Celoria 16, 20133 Milano (Italy)

    2008-08-01

    We describe in this paper a possible experiment with the existing SPARC photoinjector to test the generation of sub-picosecond high brightness electron bunches able to produce single spike radiation pulses at 500 nm in the SPARC self-amplified spontaneous emission free-electron laser (SASE-FEL). The main purpose of the experiment will be the production of short electron bunches as long as few SASE cooperation lengths and to validate scaling laws to foresee operation at shorter wavelength in the future operation with SPARX. The basic physics, the experimental parameters and 3D simulations are discussed.

  1. Investigation of 3D effects on FEL operation

    Science.gov (United States)

    van Werkhoven, G. H. C.; Faatz, B.; Schep, T. J.

    1993-07-01

    An investigation is made of 3D effects on FEL operation by comparing the 3D simulation code TDA with a 1 {1}/{2}D model. In the latter model, the full spatial dependence of the radiation field is taken into account, whereas the electrons are treated as moving in a 1D, density-averaged ponderomotive potential. Three dimensional effects like a radial beam profile, emittance and betatron oscillations are investigated. For FELIX parameters, the 1 {1}/{2}D model is in good agreement with TDA.

  2. High Average Current Electron Guns for High-Power FELs

    Science.gov (United States)

    2009-12-09

    FELs 10 Appendix B: Thermionic Injectors 11 Appendix C: Grid Fields and Bunch Emittance 13 Appendix D: PARMELA Simulation of an IOT Gun 16...Inductive Output Tube ( IOT ) amplifiers [32-34] and can generate average currents of ~1 A, peak currents of ~ 5-10 A, cathode-anode voltages of ~ 35...of grid wires, centered at z = zG and x = ±a, ±3a, ±5a, ..., is given by <D(JC,Z) = - X n = ±l.±3. Fa(x,z) Gn(x,z) ( C3 ) where *0 = (1 / 2

  3. Timing Diagnostics and Coherent Harmonics from a test-FEL

    OpenAIRE

    Cutic, Nino

    2011-01-01

    The test free-electron laser (test-FEL) at MAX-lab in Lund demonstrated for the first time circularly polarized coherent femtosecond pulses at 66 nm wavelength. A 375 MeV electron bunch was seeded by a femtosecond laser at 263 nm and coherent harmonics were extracted in an APPLE-II type elliptical undulator. A thermionic gun with a barium oxide cathode was adapted for photocathode operation, and the performance of the gun was tested. Measurements showed the production of 200 pC...

  4. FermiLib v0.1

    Energy Technology Data Exchange (ETDEWEB)

    2017-02-27

    FermiLib is an open source software package designed to facilitate the development and testing of algorithms for simulations of fermionic systems on quantum computers. Fermionic simulations represent an important application of early quantum devices with a lot of potential high value targets, such as quantum chemistry for the development of new catalysts. This software strives to provide a link between the required domain expertise in specific fermionic applications and quantum computing to enable more users to directly interface with, and develop for, these applications. It is an extensible Python library designed to interface with the high performance quantum simulator, ProjectQ, as well as application specific software such as PSI4 from the domain of quantum chemistry. Such software is key to enabling effective user facilities in quantum computation research.

  5. Design Study of a Compact Megawatt Class FEL Amplifier Based on the VISA Undulator

    CERN Document Server

    Watanabe, T; Murphy, J B; Pinayev, I P; Rose, J; Shaftan, T V; Skaritka, J; Tanabé, T; Tsang, Thomas; Wang, X J; Yu, L H

    2005-01-01

    The design of a Short Rayleigh Length (SRL) FEL amplifier based on the strong focusing VISA undulator [1] is presented in this study. The SRL FEL amplifier will be operating in the IR (0.8 - 1 μm), and consists of a two-meter VISA undulator with a peak seed laser power of about 1 kW. The FEL power and transverse mode evolution along the undulator were investigated using the three-dimensional numerical code GENESIS1.3. The evolution of the FEL output from the undulator exit to the first downstream optics is also studied. The possibility of using the proposed amplifier for a two-stage cascaded HGHG FEL [2] at the BNL SDL is also explored. The design parameters and the numerical results will be presented.

  6. Steady State Analysis of Short-wavelength, High-gainFELs in a Large Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Bane, K.; Cai, Y.; Chao, A.; Hettel, R.; /SLAC; Pellegrini, C.; /UCLA

    2007-10-15

    Storage ring FELs have operated successfully in the low-gain regime using optical cavities. Discussions of a high-gain FEL in a storage ring typically involve a special bypass to decouple the FEL interaction from the storage ring dynamics. In this paper, we investigate the coupled dynamics of a high-gain FEL in a large storage ring such as PEP and analyze the equilibrium solution. We show that an FEL in the EUV and soft x-ray regimes can be integrated into a very bright storage ring and potentially provides three orders of magnitude improvement in the average brightness at these radiation wavelengths. We also discuss possibilities of seeding with HHG sources to obtain ultra-short, high-peak power EUV and soft x-ray pulses.

  7. The Fermiac or Fermi's Trolley

    Science.gov (United States)

    Coccetti, F.

    2016-03-01

    The Fermiac, known also as Fermi's trolley or Monte Carlo trolley, is an analog computer used to determine the change in time of the neutron population in a nuclear device, via the Monte Carlo method. It was invented by Enrico Fermi and constructed by Percy King at Los Alamos in 1947, and used for about two years. A replica of the Fermiac was built at INFN mechanical workshops of Bologna in 2015, on behalf of the Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", thanks to the original drawings made available by Los Alamos National Laboratory (LANL). This reproduction of the Fermiac was put in use, and a simulation was developed.

  8. FERMI magnet power supplies: design strategies and five years of operational experience

    Science.gov (United States)

    Visintini, Roberto

    2015-05-01

    FERMI is the FEL-based light source in operation for external users since 2011 at the Elettra Research Center in Trieste, Italy. FERMI@Elettra is the name of the project for the construction and commissioning of this source. The design strategies adopted in the project had to consider the extremely close presence and the routine operation for users of the synchrotron-based source Elettra. There are more than 350 magnets and coils distributed along the linear accelerator, the two chains of undulators and the electron beam dump. Almost each magnetic element requires a dedicated DC power supply. Magnets, power supplies, and the connecting cables constitute a system, strongly interconnected with the remote control system, the machine and personnel safety system, and the infrastructure. All this has to fulfill the requirements from the particle physics specialists. We adopted a "systemic" approach in the design of new magnets and the re-use of the old ones, as well as the choice and the design of the associated power supplies. The commissioning of the systems started early 2010 and almost all magnet power supplies are in operation since then. During these 5 years, we introduced few minor upgrades and patches while the adopted solutions proved their soundness in terms of performance and reliability, causing very little downtime to the FERMI operations.

  9. Parameter analysis for a high-gain harmonic generation FEL using a recently developed 3D polychromatic code

    CERN Document Server

    Biedron, S G; Yu, L H

    2000-01-01

    One possible design for a fourth-generation light source is the high-gain harmonic generation (HGHG) free-electron laser (FEL). Here, a coherent seed with a wavelength at a subharmonic of the desired output radiation interacts with the electron beam in an energy-modulating section. This energy modulation is then converted into spatial bunching while traversing a dispersive section (a three-dipole chicane). The final step is passage through an undulator tuned to the desired higher harmonic output wavelength. The coherent seed serves to suppress and can be at a much lower subharmonic of the output radiation. Recently, a 3D code that includes multiple frequencies, multiple undulators (both in quantity and/or type), quadrupole magnets, and dipole magnets was developed to easily simulate HGHG. Here, a brief review of the HGHG theory, the code development, the Accelerator Test Facility's (ATF) HGHG FEL experimental parameters, and the parameter analysis from simulations of this specific experiment will be discussed...

  10. Comprehensive z-dependent measurements of electron-beam microbunching using COTR in a saturated SASE FEL

    CERN Document Server

    Lumpkin, Alex H; Lewellen, J W; Berg, W; Biedron, S G; Borland, M; Chae, Y; Erdmann, M; Huang, Z; Kim, K J; Li, Y; Milton, S V; Moog, E; Rule, D W; Sajaev, Vadim; Yang, B X

    2002-01-01

    We report the initial, comprehensive set of z-dependent measurements of electron-beam microbunching using coherent optical transition radiation (Cot) in a saturated self-amplified spontaneous emission (SASE) free-electron laser (FEL) experiment. In this case the FEL was operated near 530 nm using an enhanced facility including a bunch-compressed photocathode gun electron beam, linac, and 21.6 m of undulator length. The longitudinal microbunching was tracked by inserting a metal foil and mirror after each of the nine 2.4-m-long undulators and measuring the visible COTR spectra, intensity, angular, distribution, and spot size. We observed for the first time the z-dependent transition of the COTR spectra from simple lines to complex structure/sidebands near saturation. We also observed the change in the microbunching fraction after saturation, multiple fringes in the COTR interferogram that are consistent with involvement of a smaller core of the e-beam transverse distribution, and the second harmonic content of...

  11. Simulation studies of a XUV/soft X-ray harmonic-cascade FEL for the proposed LBNL recirculating linac*

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, W.M.; Barletta, W.A.; Corlett, J.N.; Zholents, A.

    2003-06-02

    Presently there is significant interest at LBNL in designing and building a facility for ultrafast (i.e. femtosecond time scale) x-ray science based upon a superconducting, recirculating RF linac (see Corlett et al. for more details). In addition to producing synchrotron radiation pulses in the 1-15 keV energy range, we are also considering adding one or more free-electron laser (FEL) beamlines using a harmonic cascade approach to produce coherent XUV soft X-ray emission beginning with a strong input seed at {approx}200 nm wavelength obtained from a ''conventional'' laser. Each cascade is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a ''virgin'' pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse, which together then undergo FEL action in the modulator. We present various results obtained with the GINGER simulation code examining final output sensitivity to initial electron beam parameters. We also discuss the effects of spontaneous emission and shot noise upon this particular cascade approach which can limit the final output coherence.

  12. Spin diffusion in Fermi gases

    DEFF Research Database (Denmark)

    Bruun, Georg

    2011-01-01

    We examine spin diffusion in a two-component homogeneous Fermi gas in the normal phase. Using a variational approach, analytical results are presented for the spin diffusion coefficient and the related spin relaxation time as a function of temperature and interaction strength. For low temperatures......, strong correlation effects are included through the Landau parameters which we extract from Monte Carlo results. We show that the spin diffusion coefficient has a minimum for a temperature somewhat below the Fermi temperature with a value that approaches the quantum limit ~/m in the unitarity regime...

  13. The Fermi Paradox is Neither Fermis Nor a Paradox

    CERN Document Server

    Gray, Robert H

    2016-01-01

    The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth-and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked 'where is everybody?'- apparently suggesting that we don't see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist, or suggesting its absence is paradoxical. The claim 'they are not here; therefore they do not exist' was first published by Michael Hart, claiming that interstellar travel and colonization of the galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important...

  14. 8-channel, FPGA based, DSP integrated cavity simulator and controller for VUV-FEL. SIMCON 3.0 Ver. 3.0. rev. 1, 06.2005 - Hardware manual

    Energy Technology Data Exchange (ETDEWEB)

    Pozniak, K.T.; Czarski, T.; Koprek, W.; Giergusiewicz, W.; Romaniuk, R.S. [Warsaw Univ. of Technology (Poland). Inst. of Electronic Systems ELHEP Laboratory

    2005-07-01

    The note describes integrated, eight channel system of hardware controller and simulator of the resonant superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now tested for the VUV FEL and developed for X-Ray FEL). The controller bases on a programmable circuit Xilinx VirtexII V4000. The solution uses DSP EMBEDDED BOARD module positioned on a Modular LLRF Control Platform. The algorithm and FPGA circuit configuration was done in the VHDL language. The internal hardware multiplication components, present in Virtex II chips, were used, to improve the floating point calculation efficiency. The implementation was achieved of a device working in the real time, according to the demands of the LLRF control system for the TESLA Test Facility (now associated with the VUV FEL machine). The device under consideration will be referred to as superconducting cavity (SCCav) SIMCON throughout this work. The manual describes hardware features of SIMCON, ver. 3.0 in modular solution. The following components are described here in detail: functional layer, parameter programming, foundations of control of particular blocks and monitoring of the real time processes. This note is accompanied by the one describing the multichannel DOOCS interface for the described hardware system. The interface was prepared in DOOCS for Solaris and in Windows. The hardware and software of 8-channel SIMCON was tested in CHECIA and ACC1 module of VUV FEL linac. The measurements results are presented. While giving all necessary technical details required to understand the work of the integrated hardware controller and simulator and to enable its practical copying, this document is a unity with other TESLA technical notes published by the same team on the subject. Thus, some modeling and other subjects were omitted, as they were addressed in detail in the quoted references. Keywords: Super conducting cavity, cavity simulator, CAVITIES CONTROLLER, SIMCON

  15. Holography, fermi surfaces and criticality

    NARCIS (Netherlands)

    Čubrović, Mihailo

    2013-01-01

    We employ the novel method of AdS/CFT correspondence to study strongly correlated fermions, their ground states and the phase transitions between them. AdS/CFT maps the quantum many-body problem to a classical gravity problem, making it more tractable. We find a holographic description of Fermi

  16. Imbalanced Fermi gases at unitarity

    NARCIS (Netherlands)

    Gubbels, K.B.; Stoof, H.T.C.

    2013-01-01

    We consider imbalanced Fermi gases with strong attractive interactions, for which Cooper-pair formation plays an important role. The two-component mixtures consist either of identical fermionic atoms in two different hyperfine states, or of two different atomic species both occupying only a single

  17. Relationship between Fermi Resonance and Solvent Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiu-Lan; LI Dong-Fei; SUN Cheng-Lin; LI Zhan-Long; YANG Guang; ZHOU Mi; LI Zuo-Wei; GAO Shu-Qin

    2011-01-01

    We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations. Also, we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures. It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio, etc., on the other hand, the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.%@@ We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations.Also,we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures.It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio,etc.,on the other hand,the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.

  18. Characteristics of the FEL project for the MUH experiment; Stato del progetto FEL per l`esperimeto MUH

    Energy Technology Data Exchange (ETDEWEB)

    Ciocci, F.; Doria, A.; Fascetti, M.; Gallerano, G.P.; Giannessi, L.; Giovenale, E.; Messina, G.; Picardi, L.; Renieri, A.; Ronci, G.; Ronsivalle, C.; Vignati, A. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione

    1999-01-01

    The design characteristics of a compact Free Electron Laser (FEL) operating in the far infrared spectral range between 200 and 600 {mu}m are presented in this report. The device can be employed in a fundamental physics experiment to be performed in collaboration with INFN-Trieste and the Paul Sherrer Institute- Villigen. Spectroscopic measurements in the above spectral region will allow one to determine the energy difference between the levels 3D-3P in the {mu}P system with great accuracy. [Italiano] In questo rapporto vengono presentate le caratteristiche di progetto di un Laser ad Elettroni Liberi (FEL) compatto operante nel lontano infrarosso a lunghezze d`onda comprese tra 200 e 600 {mu}m. Tale laser potra` essere impiegato in un esperimento di fisica fondamentale su idrogeno muonico in collaborazione con INFN-Trieste ed il Paul Sherrer Institute-Villigen. Le misure spettroscopiche nella regione spettrale del lontano infrarosso consentiranno di determinare con grande accuratezza la differenza di energia dei livelli 3D-3P nel sistema {mu}P. Attraverso la misura di questa transizione sara` possibile effettuare un test delle correzioni di Meccanica Quantistica (QED) alle energie di legame, migliorando di un ordine di grandezza l`accuratezza della misura della polarizzazione del vuoto.

  19. Performance of a Combined System Using an X-Ray FEL Oscillator and a High-Gain FEL Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, L.; Lindberg, R.; Kim, K. -J.

    2016-10-01

    The LCLS-II at SLAC will feature a 4 GeV CW superconducting (SC) RF linac [1] that can potentially drive a 5th harmonic X-Ray FEL Oscillator (XFELO) to produce fully coherent, 1 MW photon pulses with a 5 meV bandwidth at 14.4 keV [2]. The XFELO output can serve as the input seed signal for a high-gain FEL amplifier employing fs electron beams from the normal conducting SLAC linac, thereby generating coherent, fs x-ray pulses with TW peak powers using a tapered undulator after saturation [3]. Coherent, intense output at several tens of keV will also be feasible if one considers a harmonic generation scheme. Thus, one can potentially reach the 42 keV photon energy required for the MaRIE project [4] by beginning with an XFELO operating at the 3rd harmonic to produce 14.0 keV photons using a 12 GeV SCRF linac, and then subsequently using the high-gain harmonic generation scheme to generate and amplify the 3th harmonic at 42 keV [5]. We report extensive GINGER simulations that determine an optimized parameter set for the combined system.

  20. STEM education and Fermi problems

    Science.gov (United States)

    Holubova, Renata

    2017-01-01

    One of the research areas of Physics education is the study of the educational process. Investigations in this area are aimed for example on the teaching and learning process and its results. The conception of STEM education (Science, Technology, Engineering, and Mathematics) is discussed - it is one possible approach to the preparation of the curriculum and the focus on the educational process at basic and secondary schools. At schools in the Czech Republic STEM is much more realized by the application of interdisciplinary relations between subjects Physics-Nature-Technique. In both conceptions the aim is to support pupils' creativity, critical thinking, cross-curricular links. In this context the possibility of using Fermi problems in teaching Physics was discussed (as an interdisciplinary and constructivist activity). The aim of our research was the analysis of Fermi problems solving strategies, the ability of pupils to solve Fermi problems. The outcome of our analysis was to find out methods and teaching strategies which are important to use in teaching - how to solve qualitative and interdisciplinary tasks in physics. In this paper the theoretical basis of STEM education and Fermi problems will be presented. The outcome of our findings based on the research activities will be discussed so as our experiences from 10 years of Fermi problems competition that takes place at the Science Faculty, Palacky University in Olomouc. Changes in competencies of solving tasks by our students (from the point of view in terms of modern, activating teaching methods recommended by theory of Physics education and other science subjects) will be identified.

  1. Recent Progress of the NIJI-IV VUV/IR FEL

    CERN Document Server

    Sei, N; Watanabe, K W; Yamada, K Y; Yasumoto, M Y

    2005-01-01

    Free electron lasers (FELs) are being developed in a broad wavelength region from the VUV to the IR with the compact storage ring NIJI-IV at AIST. In the DUV and VUV regions, the FEL is used as an intense light source for real-time surface observation with the photoelectron emission microscopy. To extend the application field of the NIJI-IV FEL, for example to the structural analysis of proteins, experiments to obtain FEL oscillations at the wavelength below 195 nm are going on. In addition, a 3.6-m optical klystron, ETLOK-III, for developing infrared FELs has been installed in the north straight section of the NIJI-IV. Fundamental and higher harmonic spontaneous emissions from the ETLOK-III were observed in the visible and near-infrared regions. It was expected that the FEL gain for the 3rd harmonics exceed 5%. In the presentation, we will report the recent results of the VUV and IR FEL experiments.

  2. Design study of the bending sections between harmonic cascade FEL stages

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Weishi; Corlett, John; Fawley, William; Zholents, A.

    2004-06-30

    The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.

  3. Analysis of FEL-based CeC amplification at high gain limit

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Litvinenko, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Jing, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    An analysis of Coherent electron Cooling (CeC) amplifier based on 1D Free Electron Laser (FEL) theory was previously performed with exact solution of the dispersion relation, assuming electrons having Lorentzian energy distribution. At high gain limit, the asymptotic behavior of the FEL amplifier can be better understood by Taylor expanding the exact solution of the dispersion relation with respect to the detuning parameter. In this work, we make quadratic expansion of the dispersion relation for Lorentzian energy distribution and investigate how longitudinal space charge and electrons’ energy spread affect the FEL amplification process.

  4. 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.

  5. Feneric Fermi Size Enhancement of Pairing in Mesoscopic Fermi Systems

    CERN Document Server

    Farine, M; Schuck, P; Viñas, X

    2002-01-01

    The finite size dependent enhancement of pairing in mesoscopic Fermi systems is studied under the assumption that the BCS approach is valid and that the two body force is size independent. Different systems are investigated such as superconducting metallic grains and films as well as atomic nuclei. It is shown that the finite size enhancement of pairing in these systems is a surface effect which, when properly included, accounts for the data.

  6. Study of CSR Effects in the Jefferson Laboratory FEL Driver

    Energy Technology Data Exchange (ETDEWEB)

    Hall, C. C. [Colorado State U.; Biedron, S. [Colorado State U.; Burleson, Theodore A. [Colorado State U.; Milton, Stephen V. [Colorado State U.; Morin, Auralee L. [Colorado State U.; Benson, Stephen V. [JLAB; Douglas, David R. [JLAB; Evtushenko, Pavel E. [JLAB; Hannon, Fay E. [JLAB; Li, Rui [JLAB; Tennant, Christopher D. [JLAB; Zhang, Shukui [JLAB; Carlsten, Bruce E. [LANL; Lewellen, John W. [LANL

    2013-08-01

    In a recent experiment conducted on the Jefferson Laboratory IR FEL driver the effects of Coherent Synchrotron Radiation (CSR) on beam quality were studied. The primary goal of this work was to explore CSR output and effect on the beam with variation of the bunch compression in the IR chicane. This experiment also provides a valuable opportunity to benchmark existing CSR models in a system that may not be fully represented by a 1-D CSR model. Here we present results from this experiment and compare to initial simulations of CSR in the magnetic compression chicane of the machine. Finally, we touch upon the possibility for CSR induced microbunching gain in the magnetic compression chicane, and show that parameters in the machine are such that it should be thoroughly damped.

  7. Undulators to FELs: Nanometers, Femtoseconds, Coherence and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Attwood, David [University of California Berkeley

    2011-11-30

    For scientists in many fields, from material science to the life sciences and archeology, synchrotron radiation, and in particular undulator radiation, has provide an intense source of x-rays which are tunable to the absorption edges of particular elements of interest, often permitting studies at high spatial and spectral resolution. Now a close cousin to the undulator, the x-ray free electron laser (XFEL) has emerged with improved spatial coherence and, perhaps more importantly, femtosecond pulse durations which permit dynamical studies. In the future attosecond x-ray capabilities are anticipated. In this colloqium we will describe some state of the art undulator studies, how undulators work, the evolution to FELs, their pulse and coherence properties, and the types of experiments envisioned.

  8. Harmonic Operation of the SDUV HGHG-FEL

    CERN Document Server

    Dai, Z M; Xu, Y; Zhao, X F; Zhao, Z

    2005-01-01

    In this paper, we study the harmonic operation of the SDUV HGHG-FEL (Phase-I), which consists of 160MeV linac, and two undulators separated by a dispersion section. A laser light at 352nm is injected into the first undulator to modulate the energy of the electron beam. This is followed by a dispersion section to produce spatial bunching at 352nm, and a second undulator which fundamental is resonant to 264nm and 3rd harmonic is resonant to 88nm. Upon passing through the second undulator, the prebunched electron beam first radiates coherently at 88nm (i.e., the 3rd harmonic of the second undulator which is integer times of the seeding laser), and then this radiation is exponentially amplified, while the fundamental of the second undulator is allowed to grow from noise. Under proper condition, the output power of the 3rd harmonic may be much higher than that of the fundamental.

  9. Lasing Towards the VUV in the NIJI-IV FEL

    CERN Document Server

    Yamada, K; Ohgaki, H; Mikado, T; Sugiyama, S; Yamazaki, T

    2000-01-01

    The lasing wavelength in the NIJI-IV free electron laser (FEL) reached 212 nm in the deep ultraviolet (UV) range. Adoption of Al sub 2 O sub 3 /SiO sub 2 multilayer mirrors to the laser cavity, whose light absorption loss is sufficiently small even below 220 nm, compared with HfO sub 2 /SiO sub 2 usually used in the UV, was essential to shorten the wavelength in the deep UV range. The laser gain was estimated to be approx 2% around 214 nm with a peak beam current of approx 4A (average beam current of approx 20 mA) from the measured loss of the cavity degraded after the lasing experiments which agreed well with an analytic gain calculation. Lasing in the vacuum ultraviolet (VUV) range is also expected even on the compact storage ring NIJI-IV with possible enhancement of the laser gain.

  10. Present status and recent results from the APS SASE FEL

    CERN Document Server

    Lewellen, J W; Gluskin, E; Arnold, N D; Benson, C; Berg, W; Biedron, S G; Borland, M; Chae, Y C; Dejus, Roger J; Hartog, P K D; Deriy, B; Erdmann, M; Eidelman, Yu I; Hahne, M W; Huang, Z; Kim, K J; Li, Y; Lumpkin, Alex H; Makarov, O; Moog, E; Nassiri, A; Sajaev, Vadim; Soliday, R; Tieman, B J; Trakhtenberg, E; Vasserman, I B; Vinokurov, N A; Wiemerslage, G; Yang, B X

    2002-01-01

    The Low-Energy Undulator Test Line (LEUTL) at the Advanced Photon Source, Argonne National Laboratory, is intended to demonstrate the basic operation of a SASE-based free-electron laser. Goals include comparison of experimental results with theoretical predictions and scaling laws, identification of problems relevant to fourth-generation light source construction and operation and the means of addressing them, the development of operational and diagnostic techniques to optimize SASE FEL performance and increase repeatability from run to run, and performance of initial pioneering experiments capable of exploiting the unique properties of the laser. The basic layout and operational philosophy of the LEUTL experiment is presented. A summary of past results, including saturation, is reviewed, and a description of recent results is presented. We conclude with future plans, which include pressing to shorter wavelengths and incorporating user experiments into the LEUTL experimental program.

  11. Recent Results from the IR Upgrade FEL at Jefferson Lab

    CERN Document Server

    Benson, S V; Behre, C P; Biallas, G H; Boyce, J; Douglas, D; Dylla, H F D; Evans, R; Grippo, A G; Gubeli, J G; Hardy, D; Hernandez-Garcia, C; Jordan, K; Merminga, L; Neil, G; Preble, J P; Shinn, M D; Siggins, T; Walker, R L; Williams, G P; Zhang, S

    2005-01-01

    After demonstrating 10 kW operation with 1 second pulses, the Jefferson Lab program switched to demonstrating high power operation at short wavelengths using a new 8 cm period wiggler and a THz suppression chicane. We report here on the lasing results to date using this new configuration. We have demonstrated a large reduction in THz heating on the mirrors. We have also eliminated heating in the mirror steering assemblies, making operation at high power much more stable. Finally, we have greatly reduced astigmatism in the optical cavity, allowing operation with a very short Rayleigh range. The laser has been tuned from 0.9 to 3.1 microns using the new wiggler. User experiments commenced in April of 2005 with the FEL Upgrade operating over the 1-3 micron range. We are in the process of installing a 5.5 cm permanent magnet wiggler that will give us even larger tuning range and higher power.

  12. High Power Operation of the JLab IR FEL Driver Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Beard; Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Christopher Gould; Albert Grippo; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; J. Hovater; Kevin Jordan; John Klopf; Rui Li; Steven Moore; George Neil; Benard Poelker; Thomas Powers; Joseph Preble; Robert Rimmer; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Gwyn Williams; Shukui Zhang

    2007-08-01

    Operation of the JLab IR Upgrade FEL at CW powers in excess of 10 kW requires sustained production of high electron beam powers by the driver ERL. This in turn demands attention to numerous issues and effects, including: cathode lifetime; control of beamline and RF system vacuum during high current operation; longitudinal space charge; longitudinal and transverse matching of irregular/large volume phase space distributions; halo management; management of remnant dispersive effects; resistive wall, wake-field, and RF heating of beam vacuum chambers; the beam break up instability; the impact of coherent synchrotron radiation (both on beam quality and the performance of laser optics); magnetic component stability and reproducibility; and RF stability and reproducibility. We discuss our experience with these issues and describe the modus vivendi that has evolved during prolonged high current, high power beam and laser operation.

  13. Short wavelength FEL with helical micro-wiggler at FELI

    CERN Document Server

    Nakao, N; Goto, M; Ohigashi, N; Tsunawaki, Y; Moon, A; Nagai, A; Mima, K; Nakai, S; Yamanaka, C

    2000-01-01

    We are planning a short wavelength FEL experiment combining a micro-wiggler and an X-ray seed pulse. A micro-wiggler makes it possible to lase in the VUV to soft X-ray region using a low-energy electron beam. The development of the micro-wiggler is almost complete. With an intense X-ray seed pulse, quick start-up is expected making the wiggler length short. For the seed X-ray source we will use laser-produced Plasma. The validity of this concept was verified using a simulation code based on the SDE-method. With 10 kW X-ray power for seeding the saturation position is shortened to 5 m.

  14. A 300-nm compact mm-wave linac FEL design

    Energy Technology Data Exchange (ETDEWEB)

    Nassiri, A.; Kustom, R.L.; Kang, Y.W. [Argonne National Lab., IL (United States)

    1995-12-31

    Microfabrication technology offers an alternative method for fabricating precision, miniature-size components suitable for use in accelerator physics and commercial applications. The original R&D work at Argonne, in collaboration with the University of Illinois at Chicago, has produced encouraging results in the area of rf accelerating structure design, optical and x-ray masks production, deep x-ray lithography (LIGA exposures), and precision structural alignments. In this paper we will present a design study for a compact single pass mm-linac FEL to produce short wavelength radiation. This system will consists of a photocathode rf gun operated at 30 GHz, a 50-MeV superconducting constant gradient structure operated at 60 GHz, and a microundulator with 1-mm period. Initial experimental results on a scale model rf gun and microundulator will be presented.

  15. Coherent harmonic production using a two-section undulator FEL

    Energy Technology Data Exchange (ETDEWEB)

    Jaroszynski, D.A. [Commissariat a l`Energie, Bruyeres-le-Chatel (France); Prazeres, R.; Glotin, F. [Centre Universitaire Paris-Sud (France)] [and others

    1995-12-31

    We present measurements and a theoretical analysis of a new method of generating harmonic radiation in a free-electron laser oscillator with a two section undulator in a single optical cavity. To produce coherent harmonic radiation the undulator is arranged so that the downstream undulator section resonance frequency matches a harmonic of the upstream undulator. Both the fundamental and the harmonic optical fields evolve in the same optical cavity and are coupled out with different extraction fractions using a hole in one of the cavity mirrors. We present measurements that show that the optical power at the second and third harmonic can be enhanced by more than an order of magnitude in this fundamental/harmonic configuration. We compare the production of harmonic radiation of a two sectioned fundamental/harmonic undulator with that produced from a FEL operating at its highest efficiency with a step-tapered undulator, where the bunching at the end of the first section is very large. We examine, the dependence of the harmonic power on the intracavity power by adjusting the optical cavity desynchronism, {delta}L. We also examine the evolution of the fundamental and harmonic powers as a function of cavity roundtrip number to evaluate the importance of the small signal gain at the harmonic. We compare our measurements with predictions of a multi-electron numerical model that follows the evolution of fundamental and harmonic power to saturation. This fundamental/harmonic mode, of operation of the FEL may have useful applications in the production of coherent X-ray and VUV radiation, a spectral range where high reflectivity optical cavity mirrors are difficult or impossible to manufacture.

  16. Topological non-Fermi liquid

    Science.gov (United States)

    Cai, Rong-Gen; Qi, Yong-Hui; Wu, Yue-Liang; Zhang, Yun-Long

    2017-06-01

    The (2 +1 )-dimensional non-Fermi liquid (NFL) has a dual description in the (3 +1 )-dimensional anti-de Sitter (AdS) spacetime. We begin with a dyonic Reissner-Nordstrom (RN) black brane background, and consider the bulk Dirac fermion field coupled with the background U (1 ) gauge field, as well an intrinsic axial gauge field which is induced by chiral anomaly. The axial gauge field is effectively induced from the topological term in the bulk, which would lead to nontrivial effects on the boundary NFL. We study these effects through calculating the retarded Green's functions of the dual NFL holographically, in both analytical and numerical approaches. We also obtain correlation functions in the low frequency limit at zero and finite temperatures, as well as the dispersion spectrum of the Dirac cones, Fermi arc of the surface states, which can be related with the experiment.

  17. Fermi resonance in optical microcavities

    Science.gov (United States)

    Yi, Chang-Hwan; Yu, Hyeon-Hye; Lee, Ji-Won; Kim, Chil-Min

    2015-04-01

    Fermi resonance is a phenomenon of quantum mechanical superposition, which most often occurs between normal and overtone modes in molecular systems that are nearly coincident in energy. We find that scarred resonances in deformed dielectric microcavities are the very phenomenon of Fermi resonance, that is, a pair of quasinormal modes interact with each other due to coupling and a pair of resonances are generated through an avoided resonance crossing. Then the quantum number difference of a pair of quasinormal modes, which is a consequence of quantum mechanical superposition, equals periodic orbits, whereby the resonances are localized on the periodic orbits. We derive the relation between the quantum number difference and the periodic orbits and confirm it in an elliptic, a rectangular, and a stadium-shaped dielectric microcavity.

  18. On the Fermi Golden Rule

    DEFF Research Database (Denmark)

    Jensen, Arne; Nenciu, Gheorghe

    2008-01-01

    We review and further develop the framework in [9] of the stationary theory of resonances, arising by perturbation of either threshold, or embedded in the continuum, eigenvalues. While in [9] only non/degenerate eigenvalues were considered, here we add some results for the degenerate case. [9] A........ Jensen and G. Nenciu, The Fermi Golden Rule and its form at thresholds in odd dimensions. Comm. Math. Phys 261 (2006), 693-727...

  19. Topological Non-Fermi Liquid

    CERN Document Server

    Cai, Rong-Gen; Wu, Yue-Liang; Zhang, Yun-Long

    2016-01-01

    In this paper we investigate the $(2+1)$-dimensional topological non-Fermi liquid in strongly correlated electron system, which has a holographic dual description by Einstein gravity in $(3+1)$-dimensional anti-de Sitter (AdS) space-time. In a dyonic Reissner-Nordstrom black hole background, we consider a Dirac fermion coupled to the background $U(1)$ gauge theory and an intrinsic chiral gauge field $b_M$ induced by chiral anomaly. UV retarded Green's function of the charged fermion in the UV boundary from AdS$_4$ gravity is calculated, by imposing in-falling wave condition at the horizon. We also obtain IR correlation function of the charged fermion at the IR boundary arising from the near horizon geometry of the topological black hole with index $k=0,\\pm 1$. By using the UV retarded Green's function and IR correlation function, we analyze the low frequency behavior of the topological non-Fermi liquid at zero and finite temperatures, especially the relevant non-Fermi liquid behavior near the quantum critical...

  20. Enrico Fermi and the Dolomites

    CERN Document Server

    Battimelli, Giovanni

    2014-01-01

    Summer vacations in the Dolomites were a tradition among the professors of the Faculty of Mathematical and Physical Sciences at the University of Roma since the end of the XIX century. Beyond the academic walls, people like Tullio Levi-Civita, Federigo Enriques and Ugo Amaldi sr., together with their families, were meeting friends and colleagues in Cortina, San Vito, Dobbiaco, Vigo di Fassa and Selva, enjoying trekking together with scientific discussions. The tradition was transmitted to the next generations, in particular in the first half of the XX century, and the group of via Panisperna was directly connected: Edoardo Amaldi, the son of the mathematician Ugo sr., rented at least during two summers, in 1925 and in 1949, and in the winter of 1960, a house in San Vito di Cadore, and almost every year in the Dolomites; Enrico Fermi was a frequent guest. Many important steps in modern physics, in particular the development of the Fermi-Dirac statistics and the Fermi theory of beta decay, are related to scient...

  1. Enrico Fermi and the Dolomites

    Energy Technology Data Exchange (ETDEWEB)

    Battimelli, Giovanni, E-mail: giovanni.battimelli@uniroma1.it; Angelis, Alessandro de, E-mail: alessandro.de.angelis@cern.ch

    2014-11-15

    Summer vacations in the Dolomites were a tradition among the professors of the Faculty of Mathematical and Physical Sciences at the University of Roma since the end of the XIX century. Beyond the academic walls, people like Tullio Levi-Civita, Federigo Enriques and Ugo Amaldi sr., together with their families, were meeting friends and colleagues in Cortina, San Vito, Dobbiaco, Vigo di Fassa and Selva, enjoying trekking together with scientific discussions. The tradition was transmitted to the next generations, in particular in the first half of the XX century, and the group of via Panisperna was directly connected: Edoardo Amaldi, the son of the mathematician Ugo sr., rented at least during two summers, in 1925 and in 1949, and in the winter of 1960, a house in San Vito di Cadore, and almost every year in the Dolomites; Enrico Fermi was a frequent guest. Many important steps in modern physics, in particular the development of the Fermi-Dirac statistics and the Fermi theory of beta decay, are related to scientific discussions held in the region of the Dolomites.

  2. Enrico Fermi and the Dolomites

    Science.gov (United States)

    Battimelli, Giovanni; de Angelis, Alessandro

    2014-11-01

    Summer vacations in the Dolomites were a tradition among the professors of the Faculty of Mathematical and Physical Sciences at the University of Roma since the end of the XIX century. Beyond the academic walls, people like Tullio Levi-Civita, Federigo Enriques and Ugo Amaldi sr., together with their families, were meeting friends and colleagues in Cortina, San Vito, Dobbiaco, Vigo di Fassa and Selva, enjoying trekking together with scientific discussions. The tradition was transmitted to the next generations, in particular in the first half of the XX century, and the group of via Panisperna was directly connected: Edoardo Amaldi, the son of the mathematician Ugo sr., rented at least during two summers, in 1925 and in 1949, and in the winter of 1960, a house in San Vito di Cadore, and almost every year in the Dolomites; Enrico Fermi was a frequent guest. Many important steps in modern physics, in particular the development of the Fermi-Dirac statistics and the Fermi theory of beta decay, are related to scientific discussions held in the region of the Dolomites.

  3. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

    Energy Technology Data Exchange (ETDEWEB)

    Engel, Robin, E-mail: robin.engel@uni-oldenburg.de [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany); Düsterer, Stefan; Brenner, Günter [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Teubner, Ulrich [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany)

    2016-01-01

    Considering the second-order spectral correlation function of SASE-FEL radiation allows a real-time observation of the photon pulse duration during spectra acquisition. For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded.

  4. About the scheme of the infrared FEL system for the accelerator based on HF wells

    Energy Technology Data Exchange (ETDEWEB)

    Kabanov, V.S.; Dzergach, A.I. [Moscow Radiotechnical Institute (Russian Federation)

    1995-12-31

    Accelerators, based on localization of plasmoids in the HF wells (RF traps) of the axially-symmetric electromagnetic field E {sub omn} in an oversized (m,n>>1) resonant system, can give accelerating gradients {approximately}100 kV/{lambda}, e.g. 10 GV/m if {lambda}=10 {mu}m. One of possible variants of HF feeding for these accelerators is based on using the powerful infrared FEL System with 2 frequencies. The corresponding FEL`s may be similar to the Los Alamos compact Advanced FEL ({lambda}{sub 1,2}{approximately}10 pm, e-beam energy {approximately}15 MeV, e-beam current {approximately}100 A). Their power is defined mainly by the HF losses in the resonant system of the supposed accelerator.

  5. Fermi/non-Fermi mixing in SU($N$) Kondo effect

    CERN Document Server

    Kimura, Taro

    2016-01-01

    We apply conformal field theory analysis to the $k$-channel SU($N$) Kondo system, and find a peculiar behavior in the cases $N > k > 1$, which we call Fermi/non-Fermi mixing: The low temperature scaling is described as the Fermi liquid, while the zero temperature IR fixed point exhibits the non-Fermi liquid signature. We also show that the Wilson ratio is no longer universal for the cases $N > k > 1$. The deviation from the universal value of the Wilson ratio could be used as an experimental signal of the Fermi/non-Fermi mixing.

  6. Initial electron-beam characterizations for the Los Alamos APEX Facility

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Apgar, S.A.; Feldman, D.W.; O`Shea, P.G. [Los Alamos National Lab., NM (United States); Fiorito, R.B.; Rule, D.W. [Naval Surface Warfare Center, Silver Spring, MD (United States)

    1991-12-31

    The ongoing upgrade of the Los Alamos Free-Electron Laser (FEL) Facility involves the addition of a photoelectric injector (PEI) and acceleration capability to about 40 MeV. The electron-beam and high-speed diagnostics provide key measurements of charge, beam position and profile, divergence emittance, energy (centroid, spread, slew, and extraction efficiency), micropulse duration, and phase stability. Preliminary results on the facility include optical transition radiation interferometer measurements of divergence (1 to 2 mrad), FEL extraction efficiency (0.6 {plus_minus} 0.2%), and drive laser phase stability (< 2 ps [rms]). 10 refs.

  7. Initial electron-beam characterizations for the Los Alamos APEX Facility

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Apgar, S.A.; Feldman, D.W.; O' Shea, P.G. (Los Alamos National Lab., NM (United States)); Fiorito, R.B.; Rule, D.W. (Naval Surface Warfare Center, Silver Spring, MD (United States))

    1991-01-01

    The ongoing upgrade of the Los Alamos Free-Electron Laser (FEL) Facility involves the addition of a photoelectric injector (PEI) and acceleration capability to about 40 MeV. The electron-beam and high-speed diagnostics provide key measurements of charge, beam position and profile, divergence emittance, energy (centroid, spread, slew, and extraction efficiency), micropulse duration, and phase stability. Preliminary results on the facility include optical transition radiation interferometer measurements of divergence (1 to 2 mrad), FEL extraction efficiency (0.6 {plus minus} 0.2%), and drive laser phase stability (< 2 ps (rms)). 10 refs.

  8. A Coherent Compton Backscattering High Gain FEL using an X-Band Microwave Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Tantawi, S.; Dolgashev, V.; Nantista, C.; /SLAC; Pellegrini, C.; Rosenzweig, J.; Travish, G.; /UCLA

    2005-12-14

    High power microwave sources at X-Band, delivering 400 to 500 of megawatts for about 400 ns, have been recently developed. These sources can power a microwave undulator with short period and large gap, and can be used in short wavelength FELs reaching the nm region at a beam energy of about 1 GeV. We present here an experiment designed to demonstrate that microwave undulators have the field quality needed for high gain FELs.

  9. Status and Future Plans of JAERI Eergy-Recovery Linac FEL

    CERN Document Server

    Hajima, R; Kikuzawa, N; Minehara, E J; Nagai, R; Nishimori, N; Nishitani, T; Sawamura, M; Yamauchi, T

    2005-01-01

    An energy-recovery linac for a high-power free-electron laser is in operation at Japan Atomic Energy Research Institute (JAERI). In this paper, we report results of research activities and future plans of JAERI ERL-FEL, which are the construction of FEL transport line, the operation of newly-installed RF controller and IOTs, the development of super-lattice photo cathode.

  10. Expected properties of the radiation from VUV-FEL at DESY femtosecond mode of operation

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2004-01-01

    For the next three years the nominal "long pulse" (200 fs) mode of FEL operation at VUV-FEL, based on a linearized bunch compression, is not available due to the lack of a key element - a 3rd harmonic RF cavity. Essentially nonlinear compression leads naturally to a formation of a short high-current leading peak (spike) in the density distribution that produces FEL radiation. Such a mode of operation was successfully tested at VUV-FEL, Phase I. In this paper we present optimized parameters of the beam formation system that allow us to get a current spike which is bright enough to get SASE saturation for the VUV-FEL, Phase 2 at shortest design wavelength down to 6 nm. The main feature of the considered mode of operation is the production of short (15-50 fs FWHM) radiation pulses with GW-level peak power that are attractive for many users. Main parameters of the SASE FEL radiation (temporal and spectral characteristics, intensity distributions, etc.) are presented, too.

  11. Proton beam therapy facility

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-09

    It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.

  12. Active FEL-Klystrons as Formers of Femto-Second Clusters of Electromagnetic Field. Description of the Models Based on “Ordinary” FEL Sections

    Directory of Open Access Journals (Sweden)

    V.V. Kulish

    2010-01-01

    Full Text Available The qualitative properties discussion of the Femto-second active cluster FEL-klystrons, which are designed on the basis of “ordinary” FEL sections, is performed. Theoretical models of two different types of such devices are proposed. The main difference between them consists in the acceleration block arrangement. Namely, in the model with intermediate acceleration, a part of the acceleration sections is placed between the modulation and energy-transformation sections. The formulation of the problem is done. The basic system of truncated equations (in the cubic-nonlinear approximation for the complex amplitudes of harmonics of resonantly-interacting waves is obtained.

  13. Landau Theory of Helical Fermi Liquids.

    Science.gov (United States)

    Lundgren, Rex; Maciejko, Joseph

    2015-08-07

    We construct a phenomenological Landau theory for the two-dimensional helical Fermi liquid found on the surface of a three-dimensional time-reversal invariant topological insulator. In the presence of rotation symmetry, interactions between quasiparticles are described by ten independent Landau parameters per angular momentum channel, by contrast with the two (symmetric and antisymmetric) Landau parameters for a conventional spin-degenerate Fermi liquid. We project quasiparticle states onto the Fermi surface and obtain an effectively spinless, projected Landau theory with a single projected Landau parameter per angular momentum channel that captures the spin-momentum locking or nontrivial Berry phase of the Fermi surface. As a result of this nontrivial Berry phase, projection to the Fermi surface can increase or lower the angular momentum of the quasiparticle interactions. We derive equilibrium properties, criteria for Fermi surface instabilities, and collective mode dispersions in terms of the projected Landau parameters. We briefly discuss experimental means of measuring projected Landau parameters.

  14. Improvement of the beam quality by chromaticity correction for wavelength shortening in the NIJI-IV FEL

    CERN Document Server

    Sei, N; Ohgaki, H; Litvinenko, V N; Mikado, T; Yamazaki, T

    1999-01-01

    Electron-beam qualities improved by chromaticity correction in the storage ring NIJI-IV were investigated at the beam energy of 309 MeV. Sextupole-quadrupole-sextupole (SQS) magnets, which were installed in all of the short-straight sections in NIJI-IV, perfectly corrected a horizontal and a vertical chromaticity. This improvement suppressed a head-tail instability, so that higher beam current (approx 30 mA) and higher peak-electron density (approx 6x10 sup 1 sup 6 m sup - sup 3) were available for FEL experiments. The maximum FEL gain was estimated to be about 2.5% at a wavelength of 240 nm. The lasing of an FEL around 300 nm was achieved in March 1998, and the lasing of an FEL at around 240 nm was successfully observed in May 1998. The shortest wavelength of FELs with the NIJI-IV FEL system was 228 nm.

  15. Bioterrorism and the Fermi Paradox

    Science.gov (United States)

    Cooper, Joshua

    2013-04-01

    We proffer a contemporary solution to the so-called Fermi Paradox, which is concerned with conflict between Copernicanism and the apparent paucity of evidence for intelligent alien civilizations. In particular, we argue that every community of organisms that reaches its space-faring age will (1) almost immediately use its rocket-building computers to reverse-engineer its genetic chemistry and (2) self-destruct when some individual uses said technology to design an omnicidal pathogen. We discuss some of the possible approaches to prevention with regard to Homo sapiens' vulnerability to bioterrorism, particularly on a short-term basis.

  16. RF coupler for high-power CW FEL photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey); Young, L. M. (Lloyd M.)

    2003-01-01

    A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. The design presently under way is a 100-mA 2.5-cell {pi}-mode, 700-MHz, normal conducting demonstration CW RF photoinjector. This photoinjector will be capable of accelerating 3 nC per bunch with an emittance at the wiggler less than 10 mm-mrad. The paper presents results for the RF coupling from ridged wave guides to hte photoinjector RF cavity. The LEDA and SNS couplers inspired this 'dog-bone' design. Electromagnetic modeling of the coupler-cavity system has been performed using both 2-D and 3-D frequency-domain calculations, and a novel time-domain approach with MicroWave Studio. These simulations were used to adjust the coupling coefficient and calculate the power-loss distribution on the coupling slot. The cooling of this slot is a rather challenging thermal management project.

  17. A Far-Infrared FEL for the Radiation Source ELBE

    CERN Document Server

    Seidel, W; Lehnert, U; Michel, P; Schlenk, R; Willkommen, U; Wohlfarth, D; Wünsch, R

    2005-01-01

    After successfully commissioning the mid-infrared FEL (U27) and adjoining a second accelerator unit (up to 35 MeV) at ELBE we have modified our plan how to produce radiation in the far infrared.To ensure the continuous variation of the wavelength up to 150 microns we want to complement the U27 undulator by a permanent magnet undulator with a period of 100 mm (U100). The minimum gap of 24 mm and the hybrid construction consisting of Sm/Co magnets and soft iron poles ensures sufficient radiation resistance and allows rms undulator parameters up to 2.7. The large field variation allows us to cover the whole wavelength range by only two different electron energies (e.g. 20 and 35 MeV). To reduce the transverse beam size we use a partial waveguide which is 10 mm high and wide enough to allow free propagation in horizontal direction. It spans from the last quadrupole in front of the undulator up to the downstream mirror and is somewhat longer than 8 m. To minimize the coupling losses between free propagation and th...

  18. Numerical Simulation of HGHG Operation for the SDUV-FEL

    CERN Document Server

    Li, D G; Gu, Q; Xu, Y; Zhao, X F; Zhao, Z

    2005-01-01

    In this paper, we present the numerical simulation for HGHG operation of the Shanghai deep ultra-violet free electron laser source (SDUV-FEL). In this operation, a 264nm seed laser interacts with a 277MeV, 400A, normalized emittance 4mm.rad and local energy spread 0.1% electron beam in the first wiggler(modulator) with period 5cm, total length 0.8m and parameter K=2.03, where the energy of the electron beam is modulated. Then through a dispersion section with dy/dg~6.3, the energy modulation is converted to spatial bunching. In the second wiggler (radiator) with period 2.5cm, total length 10m and parameter K=1.45, the 88nm coherent radiation is generated in the first two gain lengths and its radiation power is exponentially amplified after two gain lengths. The simulation indicates that about several hundred MW 88nm and about few MW 29.3nm radiation can be produced.

  19. Extension of the spectral range of the CLIO FEL

    Energy Technology Data Exchange (ETDEWEB)

    Marcouille, O.; Boyer, J.C.; Corlier, M. [LURE, Orsay (France)] [and others

    1995-12-31

    The CLIO FEL has been designed to lase between 2 and 20 {mu}m. The electrons are produced by a 32/50 MeV RF linear accelerator. The injector is a 100 keV thermoionic gun, followed by a subharmonic prebuncher at 0.5 GHz and a buncher at 3 GHz. The electron beam is then accelerated in a 4.5 m long travelling wave accelerating section, to the nominal energy. The undulator consisted of 48 periods of 40 mm and the optical cavity is 4.8 m long which corresponds to a 1.2 m Rayleigh length. The peak power extracted by a ZnSe Brewster plate is 10 MW at 10 {mu}. But, beyond 11{mu}m, the laser power decreases rapidely and no laser oscillation appears above 17 {mu}m. In order to lase at farther wavelengths, few changes have been made: First of all, the power limit is due to the diffraction losses of the undulator vaccuum chamber (7 mm height and 2 m long). Numerical calculations have been made and show that cavity losses reach 55 % at 15 {mu}m whereas the measured gain is 60 %. Consequently, the undulator vaccuum chamber have been replaced by a approximately twice bigger one. Then, the minimum gap is increased and the maximum deflection parameter K is reduced by a factor 2: laser tunability is greatly reduced. This why a new undulator has been built. The main characteristics are summarized.

  20. Superfluid Thomas—Fermi approximation for trapped fermi gases

    Science.gov (United States)

    Hernández, E. S.; Capuzzi, P.; Szybisz, L.

    2009-02-01

    We present a generalization of fermionic fluiddynamics to the case of two trapped fermion species with a contact interaction. Within a mean field approximation, we derive coupled equations of motion for the particle densities, particle currents, and anomalous pair density. For an inhomogeneous system, the equilibrium situation with vanishing currents is described by a generalized Thomas-Fermi relation that includes the superfluid gap, together with a new nonlocal gap equation that replaces the usual BCS one. These equations are numericaly solved resorting to a local density approximation (LDA). Density and gap profiles are analyzed in terms of the scattering length, revealing that the current frame can exhibit microscopic details of quantum origin that are frequently absent in more macroscopic scenarios.

  1. Superfluid Thomas-Fermi approximation for trapped fermi gases

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, E S; Capuzzi, P; Szybisz, L [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina)], E-mail: shernand@df.uba.ar, E-mail: capuzzi@df.uba.ar, E-mail: szybisz@tandar.cnea.gov.ar

    2009-02-01

    We present a generalization of fermionic fluiddynamics to the case of two trapped fermion species with a contact interaction. Within a mean field approximation, we derive coupled equations of motion for the particle densities, particle currents, and anomalous pair density. For an inhomogeneous system, the equilibrium situation with vanishing currents is described by a generalized Thomas-Fermi relation that includes the superfluid gap, together with a new nonlocal gap equation that replaces the usual BCS one. These equations are numericaly solved resorting to a local density approximation (LDA). Density and gap profiles are analyzed in terms of the scattering length, revealing that the current frame can exhibit microscopic details of quantum origin that are frequently absent in more macroscopic scenarios.

  2. On the theory of polarized Fermi liquid

    OpenAIRE

    Mineev, V. P.

    2004-01-01

    The transport equation for transverse vibrations of magnetization in spin polarized Fermi liquid is derived from integral equation for the vertex function. The dispersion law for the transverse spin waves is established. The existance of zero-temperature spin-waves attenuation is confirmed. The problem of similar derivation in ferromagnetic "Fermi liquid" is discussed.

  3. Fermi Surface and Antiferromagnetism in Europium Metal

    DEFF Research Database (Denmark)

    Andersen, O. Krogh; Loucks, T. L.

    1968-01-01

    We have calculated the Fermi surface of europium in order to find those features which determine the wave vector of the helical moment arrangement below the Néel point. We find that there are two pieces of Fermi surface: an electron surface at the symmetry point H, which has the shape of rounded-...

  4. The Fermi paradox and coronary artery disease

    National Research Council Canada - National Science Library

    Gottlieb, Ilan; Lima, Ronaldo Souza Leão

    2014-01-01

    ..., led Fermi to ask the famous question: "Where is everybody?" Fermi was confronted with a paradox that involved probability, scale, and evidence. Coronary artery disease (CAD) presents a similar challenge. The pathophysiological importance of nonobstructive CAD is well known, as two-thirds of acute coronary syndromes (ACS) originate...

  5. Vacuum alignment and radiatively induced Fermi scale

    CERN Document Server

    Alanne, Tommi

    2016-01-01

    We extend the discussion about vacuum misalignment by quantum corrections in models with composite pseudo-Goldstone Higgs boson to renormalisable models with elementary scalars. As a concrete example, we propose a framework, where the hierarchy between the unification and the Fermi scale emerges radiatively. This scenario provides an interesting link between the unification and Fermi scale physics.

  6. Enrico Fermi significato di una scoperta

    CERN Document Server

    2001-01-01

    Questo volume è la riedizione, rinnovata ed ampliata, del volume "Enrico Fermi. Significato di una scoperta" edito dal FIEN (Forum Italiano dell'Energia Nucleare) nel 1982 e nel 1992 in occasione, rispettivamente, del 40mo e del 50mo anniversario della pila di Fermi.

  7. Biased discrete symmetry breaking and Fermi balls

    CERN Document Server

    MacPherson, A L; Macpherson, Alick L; Campbell, Bruce A

    1994-01-01

    The spontaneous breaking of an approximate discrete symmetry is considered, with the resulting protodomains of true and false vacuum being separated by domain walls. Given a strong, symmetric Yukawa coupling of the real scalar field to a generic fermion, the domain walls accumulate a gas of fermions, which modify the domain wall dynamics. The splitting of the degeneracy of the ground states results in the false vacuum protodomain structures eventually being fragmented into tiny false vacuum bags with a Fermi gas shell (Fermi balls), that may be cosmologically stable due to the Fermi gas pressure and wall curvature forces, acting on the domain walls. As fermions inhabiting the domain walls do not undergo number density freeze out, stable Fermi balls exist only if a fermion anti-fermion asymmetry occurs. Fermi balls formed with a new Dirac fermion that possesses no standard model gauge charges provide a novel cold dark matter candidate.

  8. Multi-mode competition in an FEL oscillator at perfect synchronism of an optical cavity

    CERN Document Server

    Dong, Z W; Kii, T; Yamazaki, T; Yoshikawa, K

    2002-01-01

    The sustained saturation in a short pulse free electron laser (FEL) oscillator at perfect synchronism of an optical cavity has been observed recently by Japan Atomic Energy Research Institute (JAERI) FEL group by using their super-conducting linac (Phys. Rev. Lett., in preparation). The experiments have clearly shown that FEL efficiency becomes maximum at perfect synchronism, although it has been considered that only a transient state exists at perfect synchronism due to the lethargy effect. Through careful analyses of the experimental condition of JAERI FEL, we found that, in spite of the short length of the electron micro-bunch, the saturation appears due to the following features, which were different from other FEL experiments: (1) very large ratio of the small signal gain to losses, (2) very long electron macro-bunch which can tolerate a slow start up. The saturation and high efficiency at perfect synchronism were benefited from the contribution of the weak sideband instability. In order to analyse these...

  9. PFM2: a 32 × 32 processor for X-ray diffraction imaging at FELs

    Science.gov (United States)

    Manghisoni, M.; Fabris, L.; Re, V.; Traversi, G.; Ratti, L.; Grassi, M.; Lodola, L.; Malcovati, P.; Vacchi, C.; Pancheri, L.; Benkechcache, M. E. A.; Dalla Betta, G.-F.; Xu, H.; Verzellesi, G.; Ronchin, S.; Boscardin, M.; Batignani, G.; Bettarini, S.; Casarosa, G.; Forti, F.; Giorgi, M.; Paladino, A.; Paoloni, E.; Rizzo, G.; Morsani, F.

    2016-11-01

    This work is concerned with the design of a readout chip for application to experiments at the next generation X-ray Free Electron Lasers (FEL). The ASIC, named PixFEL Matrix (PFM2), has been designed in a 65 nm CMOS technology and consists of 32 × 32 pixels. Each cell covers an area of 110 × 110 μm2 and includes a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaper used to process the preamplifier output signal, a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) and digital circuitry for channel control and data readout. Two different solutions for the readout channel, based on different versions of the time-variant filter, have been integrated in the chip. Both solutions can be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future X-ray FEL machines. The ASIC will be bump bonded to a slim/active edge pixel sensor to form the first demonstrator for the PixFEL X-ray imager. This work has been carried out in the frame of the PixFEL project funded by Istituto Nazionale di Fisica Nucleare (INFN), Italy.

  10. Feasibility Study of a Laser Beat-Wave Seeded THz FEL at the Neptune Laboratory

    CERN Document Server

    Reiche, Sven; Pellegrini, Claudio; Rosenzweig, James E; Shvets, Gennady; Tochitsky, Sergei Ya

    2005-01-01

    Free-Electron Laser in the THz range can be used to generate high output power radiation or to modulate the electron beam longitudinally on the radiation wavelength scale. Microbunching on the scale of 1-5 THz is of particular importance for potential phase-locking of a modulated electron beam to a laser-driven plasma accelerating structure. However the lack of a seeding source for the FEL at this spectral range limits operation to a SASE FEL only, which denies a subpicosecond synchronization of the current modulation or radiation with an external laser source. One possibility to overcome this problem is to seed the FEL with two external laser beams, which difference (beat-wave) frequency is matched to the resonant FEL frequency in the THz range. In this presentation we study feasibility of an experiment on laser beat-wave injection in the THz FEL considered at the UCLA Neptune Laboratory, where both a high brightness photoinjector and a two-wavelength, TW-class CO2 laser system exist. By incorporating the en...

  11. X-ray FEL Simulation with the MPP version of the GINGER Code

    Science.gov (United States)

    Fawley, William

    2001-06-01

    GINGER is a polychromatic, 2D (r-z) PIC code originally developed in the 1980's to examine sideband growth in FEL amplifiers. In the last decade, GINGER simulations have examined various aspects of x-ray and XUV FEL's based upon initiation by self-amplified spontaneous emission (SASE). Recently, GINGER's source code has been substantially updated to exploit many modern features of the Fortran90 language and extended to exploit multiprocessor hardware with the result that the code now runs effectively on platforms ranging from single processor workstations in serial mode to MPP hardware at NERSC such as the Cray-T3E and IBM-SP in full parallel mode. This poster discusses some of the numerical algorithms and structural details of GINGER which permitted relatively painless porting to parallel architectures. Examples of some recent SASE FEL modeling with GINGER will be given including both existing experiments such as the LEUTL UV FEL at Argonne and proposed projects such as the LCLS x-ray FEL at SLAC.

  12. Status report on the development of a high-power UV/IR FEL at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.; Bohn, C.; Dylla, H.F. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)] [and others

    1995-12-31

    Last year we presented a design for a kilowatt industrial UV FEL based on a superconducting RF accelerator delivering 5 mA of electron-beam current at 200 MeV with energy recovery to enhance efficiency. Since then, we have progressed toward resolving several issues associated with that design. More exact simulations of the injector have resulted in a more accurate estimate of the injector performance. A new injection method has reduced the longitudinal and transverse emittance at the linac entrance. A more compact lattice has been designed for the UV FEL, and a new recirculation scheme has been identified which greatly increases the threshold for longitudinal instabilities. We decided to use a wiggler from the Advanced Photon Source which leads to a robust high-gain FEL. Analysis of the stability of an RF control system based on CEBAF control modules indicates that only minor modifications will be needed to apply them to this FEL. Detailed magnet specifications, vacuum-chamber beam apertures, and diagnostic specifications have been developed for the recirculation arcs. The design of the optical cavity has been conceptualized, and control systems have been devised to regulate mirror distortion. A half-scale model of one of the end-corner cubes has been built and tested. Finally, three-dimensional simulations have been carried out which indicate that the FEL should exceed its minimum design goals with adequate performance margin.

  13. The DarkLight Experiment at the JLab FEL

    Science.gov (United States)

    Fisher, Peter

    2013-10-01

    DarkLight will study the production of gauge bosons associated with Dark Forces theories in the scattering of 100 MeV electrons on proton a target. DarkLight is a spectrometer to measure all the final state particles in e- + p -->e- + p +e- +e+ . QED allows this process and the invariant mass distribution of the e+e- pair is a continuum from nearly zero to nearly the electron beam energy. Dark Forces theories, which allow the dark matter mass scale to be over 1 TeV, predict a gauge boson A' in the mass range of 10-1,000 MeV and decays to an electron-positron pair with an invariant mass of mA'. We aim to search for this process using the 100 MeV, 10 mA electron beam at the JLab Free Electron Laser impinging on a hydrogen target with a 1019 cm-2 density. The resulting luminosity of 6 ×1035/cm2-s gives the experiment enough sensitivity to probe A' couplings of 10-9 α . DarkLight is unique in its design to detect all four particles in the final state. The leptons will be measured in a large high-rate TPC and a silicon sensor will measure the protons. A 0.5 T solenoidal magnetic field provides the momentum resolution and focuses the copious Møller scattering background down the beam line, away from the detectors. A first beam test has shown the FEL beam is compatible with the target design and that the hall backgrounds are manageable. The experiment has been approved by Jefferson Lab for first running in 2017.

  14. Numerical Modeling on Thermal Loading of Diamond Crystal in X-ray FEL Oscillator

    CERN Document Server

    Song, Meiqi; Guo, Yuhang; Li, Kai; Deng, Haixiao

    2015-01-01

    Due to high reflectivity and high resolution to X-ray pulse, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation free electrons lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expanding of diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillator has been systematically studied by the combined simulation of Geant4 and ANSYS, and its dependence on the environment temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented.

  15. Limitations of the transverse coherence in the self-amplified spontaneous emission FEL

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2001-01-01

    In this paper we analyze the process of the formation of transverse coherence of radiation from a self-amplified spontaneous emission (SASE) FEL. It is shown that in the high-gain linear regime the degree of transverse coherence approaches unity asymptotically as z sup - sup 1 , but not exponentially, as one would expect from a simple physical assumption that the transverse coherence is established due to the transverse mode selection. It has been found that even after finishing the transverse mode selection process the degree of transverse coherence of the radiation from SASE FEL visibly differs from unity. This is a consequence of the interdependence of the longitudinal and transverse coherence. The SASE FEL has poor longitudinal coherence which develops slowly with the undulator length thus preventing a full transverse coherence.

  16. Diagnostic Tools for Operation and Optimization of the ELBE-FEL

    CERN Document Server

    Michel, P; Lehnert, U; Schneider, C; Schurig, R; Seidel, W; Teichert, J; Wohlfarth, D

    2005-01-01

    A FEL in the mid infrared range is one of the applications of the ELBE cw-electron accelerator. The successful operation of the lasing process for the different wavelength is mainly determined by the alignment of the optical cavities, the bunch length and the energy spread of the electron beam so as the transversal adjustment of the beam through the FEL. The energy spread and the bunch length of the electron beam have their minima at different phase conditions of the accelerator. For various energy settings of the accelerator a special adjustment of both parameters has to be found for the lasing process. The presentation describes the diagnostic tools used at ELBE for the correct alignment of the optical cavity, the steering of the electron beam through the FEL and the adjustment of the electron beam parameters with respect to energy spread and bunch length.

  17. Active FEL-Klystrons As Formers of Femto-Second Clusters of Electromagnetic Field. General Description

    Directory of Open Access Journals (Sweden)

    A.Ju. Brusnik

    2010-01-01

    Full Text Available A qualitative physical and technological substantiation of the creation possibility of a new class of Femto-second Free Electron Lasers (FFELs (active cluster FEL-klystrons is given in the article. The concept of “electromagnetic field” cluster is introduced. Apart from that, the main difference between the concepts “the electromagnetic cluster” and “the radio-pulse” (which is well-known in radio-physics is formulated. The concept of “cluster electromagnetic wave” is also discussed. A general approach to designing the proposed active cluster FEL-klystrons is formulated. The description of a principal design scheme of the active cluster FEL-klystrons and their key technological basis are discussed.

  18. The magnetic and diagnostics systems for the Advanced Photon Source self-amplified spontaneously emitting FEL

    CERN Document Server

    Gluskin, E; Dejus, Roger J; Hartog, P K D; Deriy, B N; Makarov, O A; Milton, S V; Moog, E R; Ogurtsov, V I; Trakhtenberg, E; Robinson, K E; Vasserman, I B; Vinokurov, N A; Xu, S

    1999-01-01

    A self-amplified spontaneously emitting (SASE) free-electron laser (FEL) for the visible-to-ultraviolet spectral range is under construction at the Advanced Photon Source at Argonne National Laboratory. The amplifier part of the FEL consists of twelve identical 2.7-m-long sections. Each section includes a 2.4-m-long, 33-mm-period hybrid undulator, a quadrupole lens, and a set of electron beam and radiation diagnostics equipment. The undulators will operate at a fixed magnetic gap (approx. 9.3 mm) with K=3.1. The electron beam position will be monitored using capacitive beam position monitors, YAG scintillators with imaging optics, and secondary emission detectors. The spatial distribution of the photon beam will be monitored by position sensitive detectors equipped with narrow-band filters. A high-resolution spectrograph will be used to observe the spectral distribution of the FEL radiation.

  19. Comparative Design Studies for the BESSY FEL Program using the MEDUSA and GENESIS Simulation Codes

    CERN Document Server

    Freund, H

    2005-01-01

    The BESSY FEL is based on a seeded cascade of High Gain Harmonic Generation (HGHG) sections followed by an amplifier to produce coherent and stable short wavelength output. Here, we report on comparative design studies carried out using the MEDUSA [1], and GENESIS [2] simulation codes. These two codes have each been used to successfully predict a variety of FEL designs and have agreed well with a number of important experiments. In addition, they were included in a comparative study of FEL simulation [3] that reported substantial agreement between the codes for the specific configurations studied. However, these codes are based on different assumptions. GENESIS treats the particle dynamics using a wiggler-averaged orbit approximation, the transverse electromagnetic field is treated using a field solver, and harmonics are not included. MEDUSA does not use the wiggler-averaged orbit approximation to treat particle dynamics, the transverse fields are treated using a Gaussian modal superposition, and harmonics ar...

  20. IR-FEL-induced green fluorescence protein (GFP) gene transfer into plant cell

    CERN Document Server

    Awazu, K; Tamiya, E

    2002-01-01

    A Free Electron Laser (FEL) holds potential for various biotechnological applications due to its characteristics such as flexible wavelength tunability, short pulse and high peak power. We could successfully introduce the Green Fluorescent Protein (GFP) gene into tobacco BY2 cells by IR-FEL laser irradiation. The irradiated area of the solution containing BY2 cells and plasmid was about 0.1 mm sup 2. FEL irradiation at a wavelength of 5.75 and 6.1 mu m, targeting absorption by the ester bond of the lipid and the amide I bond of the protein, respectively, was shown to cause the introduction of the fluorescent dye into the cell. On the other hand, transient expression of the GFP fluorescence was only observed after irradiation at 5.75 mu m. The maximum transfer efficiency was about 0.5%.

  1. First steps towards probing chemical systems and dynamics with free-electron laser radiation--case studies at the FLASH facility

    Energy Technology Data Exchange (ETDEWEB)

    Hallmann, J; Gruebel, S; Rajkovic, I; Quevedo, W; Busse, G; Scholz, M; More, R; Petri, M; Techert, S, E-mail: stecher@gwdg.d [Max Planck Institute for Biophysical Chemistry, IFG Structural Dynamics of (Bio)chemical Systems, Am Fassberg 11, 37077 Goettingen (Germany)

    2010-10-14

    It is expected that free-electron laser (FEL) radiation with its unique properties will allow real-time tracking of structural changes during chemical reactions. The methods suggested being applied range from x-ray spectroscopy to diffraction. In order to reach this goal, in this work we will present our studies utilizing soft x-ray FEL radiation generated at the FLASH facility. We will present case studies of ultrafast x-ray diffraction on nanocrystalline lamellar assemblies of chemical relevance and heat dissipation studies on polymer foils (upon FLASH excitation) as revealed by ultrafast optical reflectivity. The extension of these studies to characterize in vacuum water jets during their interaction with FEL radiation will be given at the end if this overview. In conclusion, it can be stated that FLASH-FEL radiation can be used for studying chemical processes as long as the pulse duration is smaller than the characteristic time scales of destruction (ionization) and heat dissipation processes.

  2. Cat (Fel d 1) and dog (Can f 1) allergen levels in cars, dwellings and schools.

    Science.gov (United States)

    Niesler, A; Ścigała, G; Łudzeń-Izbińska, B

    Pets are an important source of indoor allergens. The aim of the study was to compare cat and dog allergen levels in cars, schools and homes. The study was carried out in 17 cars, 14 classrooms and 19 dwellings located in the highly industrialized and urbanized region of Poland. Dust and air samples were analyzed for Fel d 1 and Can f 1 using a double monoclonal ELISA assay. The highest amounts of cat and dog allergens (Fel d 1: 1169 μg/g; Can f 1: 277 μg/g) were found in dwellings with pets. Allergen concentrations were correlated with the number of animals kept at home. Although concentrations on automobile seats were lower, Fel d 1 levels exceeded 8 μg/g in 23.5 % of cars and high levels of Can f 1 (>10 μg/g) were found in 17.6 % of cars. The study revealed that cars of pet owners may be reservoirs of cat and dog allergens even when animals are not transported in them. In schools, concentrations of pet allergens did not reach high levels, but the moderate levels of Fel d 1 (≥1-8 μg/g) and Can f 1 (≥2-10 μg/g) were detected in 42.9 and 7.1 % of the investigated classrooms. Concentrations of cat and dog allergen in schools were higher than in homes without pets. While airborne Fel d 1 and Can f 1 levels were found low, residential allergen concentrations in settled dust and air were correlated. The study results suggest that classrooms and cars of pet owners may be important sites of exposure to cat and dog allergens, though the highest concentrations of Fel d 1 and Can f 1 are found in homes of pet owners.

  3. SOFT X-RAY FEL BY CASCADING STAGES OF HIGH GAIN HARMONIC GENERATION.

    Energy Technology Data Exchange (ETDEWEB)

    YU,L.H.

    2003-04-17

    Short wavelength Free-Electron Lasers are perceived as the next generation of synchrotron light sources. In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELs. These developments facilitate the construction of practical VUV FELs and make x-ray FELs possible. Self-Amplified Spontaneous Emission (SASE) and High Gain Harmonic Generation (HGHG)[17-19] are the two leading candidates for x-ray FELs. The first lasing of HGHG proof-of-principle experiment succeeded in August, 1999 in Brookhaven National Laboratory. The experimental results agree with the theory prediction. Compared with SASE FEL, the following advantages of HGHG FEL were confirmed; (1) Better longitudinal coherence, and hence, much narrower bandwidth than SASE. (2) More stable central wavelength, (3) More stable output energy. In this introduction, we will first briefly describe the principle of HGHG in Section A. Then in Section B, we give a general description about how to produce soft x-ray by cascading HGHG scheme. In section 2, we give a detailed description of the system design. Then, in section 3, we give a description of an analytical estimate for the HGHG process, and the calculation of the parameters of different parts of the system. The estimate is found to agree with simulation within about a factor 2 for most cases we studied. The stability issue, the sensitivity to parameter variation, the harmonic contents of the final output, and the noise degradation issue of such HGHG scheme are discussed in Section 4. The results are presented in Section 4. Finally, in Section 5, we will give some discussion of the challenges in development of the system. The conclusion is given in Section 6.

  4. Analysis of longitudinal bunching in an FEL driven two-beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lidia, S.; Gardelle, J.; Lefevre, T.; Donohue, J.T.; Gouard, P.; Rullier, J.L.; Vermare, C.

    2000-08-01

    Recent experiments have explored the use of a free-electron laser (FEL) as a buncher for a microwave two-beam accelerator, and the subsequent driving of a standing-wave rf output cavity. Here the authors present a deeper analysis of the longitudinal dynamics of the electron bunches as they are transported from the end of the FEL and through the output cavity. In particular, the authors examine the effect of the transport region and cavity aperture to filter the bunched portion of the beam.

  5. A project of accelerator-recuperator for Novosibirsk high-power FEL

    Science.gov (United States)

    Bolotin, V. P.; Vinokurov, N. A.; Kayran, D. A.; Knyazev, B. A.; Kolobanov, E. I.; Kotenkov, V. V.; Kubarev, V. V.; Kulipanov, G. N.; Matveenko, A. N.; Medvedev, L. E.; Miginsky, S. V.; Mironenko, L. A.; Oreshkov, A. D.; Ovchar, V. K.; Popik, V. M.; Salikova, T. V.; Serednyakov, S. S.; Skrinsky, A. N.; Tcheskidov, V. G.; Shevchenko, O. A.; Scheglov, M. A.

    2006-12-01

    The first stage of the Novosibirsk high-power free-electron laser (FEL) was commissioned in 2003. It is driven by a CW energy recovery linac. The next step will be the full-scale machine, a four-track accelerator-recuperator based on the same RF accelerating structure. This upgrade will permit to get shorter wavelengths in the infrared region and increase the average power of the FEL by several times. The scheme and some technical details of the project are set out. The installation will be a prototype for future multiturn accelerator-recuperators.

  6. High-performance UV/VUV optics for the Storage Ring FEL at ELETTRA

    CERN Document Server

    Gatto, A; Kaiser, N; Ristau, D; Guenster, S; Kohlhaas, J; Marsi, M; Trovò, M; Walker, R P

    2002-01-01

    Going to shorter wavelengths beyond the deep ultraviolet involves the development of dedicated optics for FEL with devoted coating techniques and characterizations. Low loss, high reflectivity dielectric mirrors with a long lifetime in a strongly harsh synchrotron radiation environment are required. In February 2001, lasing at 189.7 nm was obtained with Al sub 2 O sub 3 /SiO sub 2 Ion Beam Sputtering mirrors, the shortest wavelength obtained so far with FEL oscillators. In July 2001, 330 mW extracted power was measured with optimized transmission mirrors. Coating research and development correlated to lasing performance obtained so far is reported.

  7. Design and optimization of the grating monochromator for soft X-ray self-seeding FELs

    Energy Technology Data Exchange (ETDEWEB)

    Serkez, Svitozar

    2015-10-15

    The emergence of Free Electron Lasers (FEL) as a fourth generation of light sources is a breakthrough. FELs operating in the X-ray range (XFEL) allow one to carry out completely new experiments that probably most of the natural sciences would benefit. Self-amplified spontaneous emission (SASE) is the baseline FEL operation mode: the radiation pulse starts as a spontaneous emission from the electron bunch and is being amplified during an FEL process until it reaches saturation. The SASE FEL radiation usually has poor properties in terms of a spectral bandwidth or, on the other side, longitudinal coherence. Self-seeding is a promising approach to narrow the SASE bandwidth of XFELs significantly in order to produce nearly transformlimited pulses. It is achieved by the radiation pulse monochromatization in the middle of an FEL amplification process. Following the successful demonstration of the self-seeding setup in the hard X-ray range at the LCLS, there is a need for a self-seeding extension into the soft X-ray range. Here a numerical method to simulate the soft X-ray self seeding (SXRSS) monochromator performance is presented. It allows one to perform start-to-end self-seeded FEL simulations along with (in our case) GENESIS simulation code. Based on this method, the performance of the LCLS self-seeded operation was simulated showing a good agreement with an experiment. Also the SXRSS monochromator design developed in SLAC was adapted for the SASE3 type undulator beamline at the European XFEL. The optical system was studied using Gaussian beam optics, wave optics propagation method and ray tracing to evaluate the performance of the monochromator itself. Wave optics analysis takes into account the actual beam wavefront of the radiation from the coherent FEL source, third order aberrations and height errors from each optical element. The monochromator design is based on a toroidal VLS grating working at a fixed incidence angle mounting without both entrance and exit

  8. Beam Line Commissioning of a UV/VUV FEL at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Stephen; Blackburn, Keith; Bullard, Daniel; Clavero Perez, Cesar; Coleman, James; Dickover, Cody; Douglas, David; Ellingsworth, Forrest; Evtushenko, Pavel; Hernandez-Garcia, Carlos; Gould, Christopher; Gubeli, Joseph; Hardy, David; Jordan, Kevin; Klopf, John; James, Kortze; Legg, Robert; Marchlik, Matthew; Moore, Steven; Neil, George; Powers, Thomas; Sexton, Daniel; Shinn, Michelle D; Tennant, Christopher; Walker, Richard; Williams, Gwyn; Wilson, Frederick

    2011-08-01

    Many novel applications in photon sciences require very high brightness and/or short pulses in the vacuum ultra-violet (VUV). Jefferson Lab has commissioned a UV oscillator with high gain and has transported the third harmonic of the UV to a user lab. The experimental performance of the UV FEL is much better than simulated performance in both gain and efficiency. This success is important for efforts to push towards higher gain FELs at short wavelengths where mirrors absorb strongly. We will report on efforts to characterize the UV laser and the VUV coherent harmonics as well as designs to lase directly in the VUV wavelength range.

  9. Quantum chaos on a critical Fermi surface

    CERN Document Server

    Patel, Aavishkar A

    2016-01-01

    We compute parameters characterizing many-body quantum chaos for a critical Fermi surface without quasiparticle excitations. We examine a theory of $N$ species of fermions at non-zero density coupled to a $U(1)$ gauge field in two spatial dimensions, and determine the Lyapunov rate and the butterfly velocity in an extended RPA approximation. The thermal diffusivity is found to be universally related to these chaos parameters, i.e. the relationship is independent of $N$, the gauge coupling constant, the Fermi velocity, the Fermi surface curvature, and high energy details.

  10. Radiatively induced Fermi scale and unification

    CERN Document Server

    Alanne, Tommi

    2016-01-01

    We propose a framework, where the hierarchy between the unification and the Fermi scale emerges radiatively. This work tackles the long-standing question about the connection between the low Fermi scale and a more fundamental scale of Nature. As a concrete example, we study a Pati-Salam-type unification of Elementary-Goldstone-Higgs scenario, where the Standard Model scalar sector is replaced by an SU(4)-symmetric one, and the observed Higgs particle is an elementary pseudo-Goldstone boson. We construct a concrete model where the unification scale is fixed to a phenomenologically viable value, while the Fermi scale is generated radiatively. This scenario provides an interesting link between the unification and Fermi scale physics, and opens up prospects for exploring a wide variety of open problems in particle physics, ranging from neutrinos to cosmic inflation.

  11. Fermi: physicist with a capital F

    Science.gov (United States)

    Cobal, Marina

    2016-12-01

    Enrico Fermi – one of the great physicists of the 21st century – was a beacon for every Italian student of physics. This is wonderfully captured in The Pope of Physics by Gino Segrè and Bettina Hoerlin.

  12. Fermi Surface of the Most Dilute Superconductor

    Science.gov (United States)

    Lin, Xiao; Zhu, Zengwei; Fauqué, Benoît; Behnia, Kamran

    2013-04-01

    The origin of superconductivity in bulk SrTiO3 is a mystery since the nonmonotonous variation of the critical transition with carrier concentration defies the expectations of the crudest version of the BCS theory. Here, employing the Nernst effect, an extremely sensitive probe of tiny bulk Fermi surfaces, we show that, down to concentrations as low as 5.5×1017cm-3, the system has both a sharp Fermi surface and a superconducting ground state. The most dilute superconductor currently known therefore has a metallic normal state with a Fermi energy as little as 1.1 meV on top of a band gap as large as 3 eV. The occurrence of a superconducting instability in an extremely small, single-component, and barely anisotropic Fermi surface implies strong constraints for the identification of the pairing mechanism.

  13. Gamma-Ray Astrophysics NSSTC Fermi GBM

    Data.gov (United States)

    National Aeronautics and Space Administration — The Fermi Gamma-Ray Burst Monitor (GBM) is not a pointed or imaging instrument. To determine fluxes for known sources, we measure the change in the count rate...

  14. Fermi's Conundrum: Proliferation and Closed Societies

    Science.gov (United States)

    Teller, Wendy; Westfall, Catherine

    2007-04-01

    On January 1, 1946 Emily Taft Douglas, a freshman Representative at Large for Illinois, sent a letter to Enrico Fermi. She wanted to know whether, if atomic energy was used for peaceful purposes, it might be possible to clandestinely divert some material for bombs. Douglas first learned about the bomb not quite five months before when Hiroshima was bombed. Even though she was not a scientist she identified a key problem of the nuclear age. Fermi responded with requirements to allow peaceful uses of atomic energy and still outlaw nuclear weapons. First, free interchange of information between people was required, and second, people who reported possible violations had to be protected. Fermi had lived in Mussolini's Italy and worked under the war time secrecy restrictions of the Manhattan Project. He was not optimistic that these conditions could be met. This paper discusses how Douglas came to recognize the proliferation issue and what led Fermi to his solution and his pessimism about its practicality.

  15. A fast algorithm for finding point sources in the Fermi data stream: FermiFAST

    Science.gov (United States)

    Asvathaman, Asha; Omand, Conor; Barton, Alistair; Heyl, Jeremy S.

    2017-04-01

    We present a new and efficient algorithm for finding point sources in the photon event data stream from the Fermi Gamma-Ray Space Telescope, FermiFAST. The key advantage of FermiFAST is that it constructs a catalogue of potential sources very fast by arranging the photon data in a hierarchical data structure. Using this structure, FermiFAST rapidly finds the photons that could have originated from a potential gamma-ray source. It calculates a likelihood ratio for the contribution of the potential source using the angular distribution of the photons within the region of interest. It can find within a few minutes the most significant half of the Fermi Third Point Source catalogue (3FGL) with nearly 80 per cent purity from the 4 yr of data used to construct the catalogue. If a higher purity sample is desirable, one can achieve a sample that includes the most significant third of the Fermi 3FGL with only 5 per cent of the sources unassociated with Fermi sources. Outside the Galactic plane, all but eight of the 580 FermiFAST detections are associated with 3FGL sources. And of these eight, six yield significant detections of greater than 5σ when a further binned likelihood analysis is performed. This software allows for rapid exploration of the Fermi data, simulation of the source detection to calculate the selection function of various sources and the errors in the obtained parameters of the sources detected.

  16. Coexistence of Fermi arcs and Fermi pockets in a high-T(c) copper oxide superconductor.

    Science.gov (United States)

    Meng, Jianqiao; Liu, Guodong; Zhang, Wentao; Zhao, Lin; Liu, Haiyun; Jia, Xiaowen; Mu, Daixiang; Liu, Shanyu; Dong, Xiaoli; Zhang, Jun; Lu, Wei; Wang, Guiling; Zhou, Yong; Zhu, Yong; Wang, Xiaoyang; Xu, Zuyan; Chen, Chuangtian; Zhou, X J

    2009-11-19

    In the pseudogap state of the high-transition-temperature (high-T(c)) copper oxide superconductors, angle-resolved photoemission (ARPES) measurements have seen Fermi arcs-that is, open-ended gapless sections in the large Fermi surface-rather than a closed loop expected of an ordinary metal. This is all the more puzzling because Fermi pockets (small closed Fermi surface features) have been suggested by recent quantum oscillation measurements. The Fermi arcs cannot be understood in terms of existing theories, although there is a solution in the form of conventional Fermi surface pockets associated with competing order, but with a back side that is for detailed reasons invisible to photoemission probes. Here we report ARPES measurements of Bi(2)Sr(2-x)La(x)CuO(6+delta) (La-Bi2201) that reveal Fermi pockets. The charge carriers in the pockets are holes, and the pockets show an unusual dependence on doping: they exist in underdoped but not overdoped samples. A surprise is that these Fermi pockets appear to coexist with the Fermi arcs. This coexistence has not been expected theoretically.

  17. Conoscere Fermi nel centenario della nascita : 29 settembre 1901 - 2001

    CERN Document Server

    Bonolis, Luisa

    2001-01-01

    Il lavoro scientifico di Fermi riguarda molti campi disparati, ciascuno dei quali ha avuto uno sviluppo peculiare in tempi successivi alla morte. In questo volume un certo numero di specialisti contemporanei di ciascun settore espone in forma semplice l'idea originaria e la sua successiva evoluzione. INDICE. Carlo Bernardini, "Introduzione"; Giorgio Salvini, "Enrico Fermi. La sua vita, ed un commento alla sua opera"; Edoardo Amaldi, "Commemorazione del Socio Enrico Fermi"; Enrico Persico, "Commemorazione di Enrico Fermi"; Franco Rasetti, "Enrico Fermi e la Fisica Italiana"; Franco Bassani, "Enrico Fermi e la Fisica dello Stato Solido"; Giorgio Parisi, "La statistica di Fermi"; Giovanni Gallavotti, "La meccanica classica e la rivoluzione quantistica nei lavori giovanili di Fermi"; Tullio Levi-Civita, "Sugli invarianti adiabatici"; Bruno Bertotti, "Le coordinate di Fermi e il Principio di Equivalenza"; Marcello Cini, "Fermi e l'elettrodinamica quantistica"; Nicola Cabibbo. "Le interazioni deboli"; Ugo Amaldi, "...

  18. Strongly Interacting Fermi Gases in Two Dimensions

    Science.gov (United States)

    2012-07-17

    Svistunov, M. Ku, A. Sommer, L. W. Cheuk, A. Schirotzek, M. W. Zwierlein Feynman diagrams versus Fermi-gas Feynman emulator Nature Physics 8... Feynman emulator. Nature Physics 8, 366 (2012) 4. Jee Woo Park, Cheng-Hsun Wu, Ibon Santiago, Tobias G. Tiecke, Peyman Ahmadi, Martin W. Zwierlein...chapters 7. M. Randeria, W. Zwerger, and M. Zwierlein. The BEC-BCS Crossover and the Unitary Fermi Gas. Lecture Notes in Physics , Volume 836, edited by

  19. Fermi breakup and the statistical multifragmentation model

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, B.V., E-mail: brett@ita.br [Departamento de Fisica, Instituto Tecnologico de Aeronautica - CTA, 12228-900 Sao Jose dos Campos (Brazil); Donangelo, R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Julio Herrera y Reissig 565, 11.300 Montevideo (Uruguay); Souza, S.R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, CP 15051, 91501-970, Porto Alegre (Brazil); Lynch, W.G.; Steiner, A.W.; Tsang, M.B. [Joint Institute for Nuclear Astrophysics, National Superconducting Cyclotron Laboratory and the Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-02-15

    We demonstrate the equivalence of a generalized Fermi breakup model, in which densities of excited states are taken into account, to the microcanonical statistical multifragmentation model used to describe the disintegration of highly excited fragments of nuclear reactions. We argue that such a model better fulfills the hypothesis of statistical equilibrium than the Fermi breakup model generally used to describe statistical disintegration of light mass nuclei.

  20. Fermi-Dirac Statistics of Complex Networks

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi; ZHU Di-Ling; LIU Wei-Ming

    2005-01-01

    @@ We investigate phenomena of decline of complex networks by employing and analysing an illness model. Its intrinsic relation with the Fermi distribution is shown and a mapping to Fermi gas is established. The results of numerical simulations are obtained in two ways. We also compare the model with other models, including the dual relationship with the fitness model, and its difference from the Cayley tree model.

  1. Understanding and Using the Fermi Science Tools

    Science.gov (United States)

    Asercion, Joseph; Fermi Science Support Center

    2017-01-01

    The Fermi Science Support Center (FSSC) provides information, documentation, and tools for the analysis of Fermi science data, including both the Large-Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). Source and binary versions of the Fermi Science Tools can be downloaded from the FSSC website, and are supported on multiple platforms. An overview document, the Cicerone, provides details of the Fermi mission, the science instruments and their response functions, the science data preparation and analysis process, and interpretation of the results. Analysis Threads and a reference manual available on the FSSC website provide the user with step-by-step instructions for many different types of data analysis: point source analysis - generating maps, spectra, and light curves, pulsar timing analysis, source identification, and the use of python for scripting customized analysis chains. We present an overview of the structure of the Fermi science tools and documentation, and how to acquire them. We also provide examples of standard analyses, including tips and tricks for improving Fermi science analysis.

  2. 77 FR 75660 - Agency Information Collection Activities; Proposed Collection; Comments Requested: FEL Out-of...

    Science.gov (United States)

    2012-12-21

    ... Collection; Comments Requested: FEL Out-of-Business Records ACTION: 30-day notice. The Department of Justice... comment until January 22, 2013. This process is conducted in accordance with 5 CFR 1320.10. Written... the burden of the proposed collection of information, including the validity of the methodology and...

  3. Start-To-End Simulations of the Energy Recovery Linac Prototype FEL

    CERN Document Server

    Gerth, Christopher; Muratori, Bruno; Owen, Hywel; Thompson, Neil R

    2004-01-01

    Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that serves as a testbed for the study of beam dynamics and accelerator technology important for the design and construction of the proposed 4th Generation Light Source (4GLS) project. Two major objectives for the ERLP are the operation of an oscillator infra-red FEL and demonstration of energy recovery from an electron bunch with an energy spread induced by the FEL. In this paper we present start-to-end simulations including the FEL of the ERLP. The beam dynamics in the high-brightness injector, which consists of a DC photocathode gun and a super-conducting booster, have been modelled using the particle tracking code ASTRA. After the main linac, in which the particles are accelerated to 35 MeV, particles have been tracked with the code ELEGANT. The 3D code GENESIS was used to model the FEL interaction with the electron beam. Different modes of operation and their impact on the design of the ERLP are discussed.

  4. Generation of doublet spectral lines at self-seeded X-ray FELs

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2010-01-01

    Self-seeding schemes, consisting of two undulators with a monochromator in between, aim to reduce the bandwidth of SASE X-ray FELs. We recently proposed a new method of monochromatization exploiting a single crystal in Bragg-transmission geometry for self-seeding in the hard X-ray range. A straightforward extension is to use such kind of monochromator setup with two -or more- crystals arranged in a series to spectrally filter the SASE radiation at two closely-spaced wavelengths within the FEL gain band. This allows for the production of doublet -or multiplet- spectral lines. Applications involve any process with a large change in cross section over a narrow wavelength range, as in multiple wavelength anomalous diffraction. Here we consider the simultaneous operation of the LCLS hard X-ray FEL at two closely spaced wavelengths. We present simulation results for the LCLS baseline, yielding fully coherent radiation shared between two longitudinal modes. Mode spacing can be easily tuned within the FEL gain band. ...

  5. 3D simulations on output power fluctuation in a short bunch rf-linac FEL

    Science.gov (United States)

    Sentoku, Y.; Furukawa, H.; Mima, K.; Taguchi, T.; Kuruma, S.; Yasuda, H.; Yamanaka, C.; Nakai, S.

    1995-04-01

    A space-time dependent 3D simulation code has been developed in order to analyze the RF-linac FEL oscillator dynamics. Our simulation code employed both the transverse mode spectral method and the longitudinal finite difference method. The electron beam is modeled by a group of super particles which have a density profile in the time domain. In this model the electron beam is able to determine the energy spread and the finite emittance. This simulation code enables us to describe the transverse mode competition and the slippage effects in the resonator cavity. In this paper, a high power infrared FEL with a short bunch electron beam is investigated. The output power fluctuation with cavity desynchronism is simulated with this code. Especially, we investigated the effects of the transverse mode competition, energy spread, and the finite emittance of the electron beam on the output fluctuation. Using FELIX parameters, the FEL oscillator is simulated for 300 passes. The output power oscillates periodically in the case of single transverse mode and not in the case of multi-transverse modes. In a warm beam with multi-transverse modes, the emission is higher than that with a single mode, and the optical pulse shape is almost the after 100 passes. Furthermore, the phase space motion of the laser field is periodic and stable. As a result of the simulation, we recommend that high power infrared FEL operation should include multi-transverse modes in order to get higher emission and a more stable optical pulse.

  6. Commissioning of the accelerator-recuperator for the FEL at the Siberian Center for Photochemical Research.

    Science.gov (United States)

    Antokhin, E I; Akberdin, R R; Bokov, M A; Bolotin, V P; Deichuli, O I; Dementyev, E N; Dubrovin, A N; Dovgenko, B A; Evtushenko, Yu A; Gavrilov, N G; Gorniker, E I; Kairan, D A; Kholopov, M A; Kiselev, O B; Kolmogorov, V V; Kolobanov, E I; Kondakov, A A; Kondakova, N L; Krutikhin, S A; Kubarev, V V; Kulipanov, G N; Kuper, E A; Kuptsov, I V; Kurkin, G Ya; Leontyevskaya, L G; Loskutov, V Yu; Medvedev, L E; Medvedko, A S; Miginsky, S V; Mironenko, L A; Oreshkov, A D; Ovchar, V K; Petrov, S P; Petrov, V M; Popik, V M; Rotov, E A; Salikova, T V; Sedlyarov, I K; Scheglov, M A; Serednyakov, S S; Shevchenko, O A; Shubin, E I; Skrinsky, A N; Tararyshkin, S V; Timoshina, L A; Tribendis, A G; Veremeenko, V F; Vinokurov, N A; Vobly, P D; Zagorodnikov, E I; Zaigrayeva, N S

    2003-09-01

    A 100 MeV eight-turn accelerator-recuperator intended to drive a high-power infrared free-electron laser (FEL) is currently under construction in Novosibirsk. The first stage of the machine includes a one-turn accelerator-recuperator that contains a full-scale RF system. It was commissioned successfully in June 2002.

  7. Deposition of robust multilayer mirror coatings for storage ring FEL lasing at 176nm

    Science.gov (United States)

    Günster, St.; Ristau, D.; Trovó, M.; Danailov, M.; Gatto, A.; Kaiser, N.; Sarto, F.; Piegari, A.

    2005-09-01

    Progress was achieved in the last years in the development of multilayer mirrors used in storage ring Free Electron Lasers (FEL) operating in the vacuum ultraviolet spectral range. Based on dense oxide coatings deposited by Ion Beam Sputtering, a stable lasing at 190 nm was demonstrated. The extension towards shorter wavelengths had to overcome severe problems connected to the radiation resistance and the necessary reflectivity of the resonator mirrors. In this context, radiation resistance can be considered as the ability of the mirror materials to withstand the high power laser radiation and the intense energetic background radiation generated in the synchrotron source. The bombardment with high energetic photons leads to irreversible changes and a coloration on the specimen. Reflectivity requirements can be evaluated from the tolerable losses of FEL systems. At ELETTRA FEL the resonator mirror reflectivity must be above 95 %. Evaporated fluoride multilayer mirrors provide sufficient reflectivity, but they do not exhibit an adequate radiation resistance. Pure oxide multilayers show a sufficient radiation resistance, but they cannot reach the necessary reflectivity below 190 nm. A successful approach combines evaporated fluoride multilayer stack with a dense protection layer of silicon dioxide deposited by Ion Beam Sputtering. Such mirror systems were produced reaching a reflectivity of approximately 99 % at 180 nm. Lasing in the storage ring FEL at ELETTRA was realised in the range between 176 - 179 nm. The mirror reflectivity shows only a slight degradation after lasing, which could be fully restored after the lasing experiment.

  8. An Electron Bunch Compressor Based on an FEL Interaction in the Far Infra Red

    OpenAIRE

    Gaupp, Andreas

    2013-01-01

    In this note an electron bunch compressor is proposed based on FEL type interaction of the electron bunch with far infrared (FIR) radiation. This mechanism maintains phase space density and thus requires a high quality electron beam to produce bunches of the length of a few ten micrometer.

  9. Numerical modeling of thermal loading of diamond crystal in X-ray FEL oscillators

    Science.gov (United States)

    Song, Mei-Qi; Zhang, Qing-Min; Guo, Yu-Hang; Li, Kai; Deng, Hai-Xiao

    2016-04-01

    Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design. Supported by National Natural Science Foundation of China (11175240, 11205234, 11322550) and Program for Changjiang Scholars and Innovative Research Team in University (IRT1280)

  10. Study on wavelength shortening and upgrading of the free electron laser (FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Tetsuo; Yamada, Kawakatsu; Sei, Norihiro; Ohgaki, Hideaki; Sugiyama, Suguru; Mikado, Tomohisa [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

    1997-02-01

    This study is a task of ``Comprehensive study`` in ``nuclear energy basic technology research``, which is promoted under cooperation of four research institutes. The Electrotechnical Laboratory conducted, in 1991 in the first period of colaboration, on successful oscillation at visible region (598 nm) as the first case in Japan, construction of small type accumulation ring NIJI-IV for FEL, successful oscillation of visible range from 595 to 488 nm by installing optical krystron with maximum frequency in the world, and successful emittance lowering of accumulation beam by wide improvement of the ring. In the optical resonator, studies on minute loss measuring technique and on recovery from mirror deterioration were promoted. In the second period started from fiscal year of 1994, studies on FEL oscillation technique in short wavelength and upgrading of FEL corresponding to a frontier area were started, to succeed an oscillation experiment at 350 nm in ultraviolet area on April, 1994. Then, studies on generation of high luminescence x-ray owing to laser Compton scattering using FEL as a future plan, on design of a new accumulation ring and on the others as well as studies on further quality improvement of electron beam and on optical resonator have been promoted. (G.K.)

  11. Microbunching Instability Effect Studies and Laser Heater Optimization for the SPARX FEL Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Vaccarezza, C.; Chiadroni, E.; Ferrario, M.; Giannessi, L.; Quattromini, M.; Ronsivalle, C.; Venturini, C.; Migliorati, M.; Dattoli, G.

    2010-05-23

    The effects of microbunching instability for the SPARX accelerator have been analyzed by means of numerical simulations. The laser heater counteracting action has been addressed in order to optimize the parameters of the compression system, either hybrid RF plus magnetic chicane or only magnetic, and possibly enhance the FEL performance.

  12. Performance of the SASE amplifier of the TEU-FEL project

    NARCIS (Netherlands)

    Ernst, G.J.; Goldstein, J.C.

    1992-01-01

    The free-electron laser of the TEU-FEL project of the University of Twente will be driven by a photoinjector followed by a racetrack microtron. The injector, which is now under construction, will provide a very high-brightness electron beam with an energy of about 6 MeV. In phase I of the project, e

  13. The Gain and Efficiency Enhancement in Double-Undulator Fels Induced Betatron Oscillations

    NARCIS (Netherlands)

    Bazylev, V. A.; Tulupov, A. V.

    1993-01-01

    A new construction of a free-electron laser using induced betatron oscillations to increase the FEL gain or efficiency is proposed. Induced betatron oscillations are driven by an additional space-periodic magnetic field with a period close to that of electron betatron oscillations in an undulator

  14. Powerful electrostatic FEL: Regime of operation, recovery of the spent electron beam and high voltage generator

    Energy Technology Data Exchange (ETDEWEB)

    Boscolo, I. [Univ. and INFN, Milan (Italy); Gong, J. [Southwest Jiaotong Univ., Chengdu (China)

    1995-02-01

    FEL, driven by a Cockcroft-Walton electrostatic accelerator with the recovery of the spent electron beam, is proposed as powerful radiation source for plasma heating. The low gain and high gain regimes are compared in view of the recovery problem and the high gain regime is shown to be much more favourable. A new design of the onion Cockcroft-Walton is presented.

  15. The cat lipocalin Fel d 7 and its cross-reactivity with the dog lipocalin Can f 1.

    Science.gov (United States)

    Apostolovic, D; Sánchez-Vidaurre, S; Waden, K; Curin, M; Grundström, J; Gafvelin, G; Cirkovic Velickovic, T; Grönlund, H; Thomas, W R; Valenta, R; Hamsten, C; van Hage, M

    2016-10-01

    We investigated the prevalence of sensitization to the cat lipocalin Fel d 7 among 140 cat-sensitized Swedish patients and elucidated its allergenic activity and cross-reactivity with the dog lipocalin Can f 1. Sixty-five of 140 patients had IgE to rFel d 7 whereof 60 also had IgE to rCan f 1. A moderate correlation between IgE levels to rFel d 7 and rCan f 1 was found. rFel d 7 activated basophils in vitro and inhibited IgE binding to rCan f 1 in 4 of 13 patients, whereas rCan f 1 inhibited IgE binding to rFel d 7 in 7 of 13 patients. Fel d 7 and Can f 1 showed high similarities in protein structure and epitopes in common were found using cross-reactive antisera. Fel d 7 is a common allergen in a Swedish cat-sensitized population that cross-reacts with Can f 1, and may contribute to symptoms in cat- but also in dog-allergic patients.

  16. The role of radiation reaction in Lienard-Wiechert description of FEL interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kimel, I.; Elias, L.R. [Univ. of Central Florida, Orlando, FL (United States)

    1995-12-31

    The most common theoretical analysis of the FEL interaction is based on the set of equations consisting of Lorentz and wave equations. This approach explains most of FEL features and, in particular, works well to describe operation in the amplifier mode. In that approach however, there are some difficulties in describing operation in oscillator mode, as well as self amplified spontaneous emission. In particular, it is not possible to describe the start up stage since there is no wave to start with. It is clear that a different approach is required in such situations. That is why we have pursued the study of the FEL interaction in the framework of Lorentz plus Lienard-Wiechert equations. The Lienard-Wiechert Lorentz equation approach however, presents its own set of problems. Variation in energy of the electrons is given exclusively by the Lorentz equation. Thus, the energy lost due to the radiation process is not properly taken into account. This, of course, is a long standing problem in classical electrodynamics. In order to restore energy conservation radiation reaction has to be incorporated into the framework. The first question in that regard has to do with which form of the radiation reaction equations is the most convenient for computations in the FEL process. This has to do with the fact that historically, radiation reaction has been added in an ad hoc manner instead of being derived from the fundamental equations. Another problem discussed is how to take into account the radiation reaction in a collective manner in the interaction among electrons. Also discussed is the radiation reaction vis a vi the coherence properties of the FEL process.

  17. Amplification of current density modulation in a FEL with an infinite electron beam

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-28

    We show that the paraxial field equation for a free electron laser (FEL) in an infinitely wide electron beam with {kappa}-2 energy distribution can be reduced to a fourth ordinary differential equation (ODE). Its solution for arbitrary initial phase space density modulation has been derived in the wave-vector domain. For initial current modulation with Gaussian profile, close form solutions are obtained in space-time domain. In developing an analytical model for a FEL-based coherent electron cooling system, an infinite electron beam has been assumed for the modulation and correction processes. While the assumption has its limitation, it allows for an analytical close form solution to be obtained, which is essential for investigating the underlying scaling law, benchmarking the simulation codes and understanding the fundamental physics. 1D theory was previously applied to model a CeC FEL amplifier. However, the theory ignores diffraction effects and does not provide the transverse profile of the amplified electron density modulation. On the other hand, 3D theories developed for a finite electron beam usually have solutions expanded over infinite number of modes determined by the specific transverse boundary conditions. Unless the mode with the largest growth rate substantially dominates other modes, both evaluation and extracting scaling laws can be complicated. Furthermore, it is also preferable to have an analytical FEL model with assumptions consistent with the other two sections of a CeC system. Recently, we developed the FEL theory in an infinitely wide electron beam with {kappa}-1 (Lorentzian) energy distribution. Close form solutions have been obtained for the amplified current modulation initiated by an external electric field with various spatial-profiles. In this work, we extend the theory into {kappa}-2 energy distribution and study the evolution of current density induced by an initial density modulation.

  18. A helical optical for circular polarized UV-FEL project at the UVSOR

    Energy Technology Data Exchange (ETDEWEB)

    Hama, Hiroyuki [Institute for Molecular Science, Okazaki (Japan)

    1995-12-31

    Most of existing storage ring free electron lasers (SRFEL) are restricted those performances by degradation of mirrors in optical cavities. In general, the SRFEL gain at the short wavelength region with high energy electrons is quite low, and the high reflectivity mirrors such as dielectric multilayer mirrors are therefore required. The mirror degradation is considered as a result of irradiation of higher harmonic photons that are simultaneously emitted from planar optical klystron (OK) type undulators, which are commonly used in SRFEL. This problem is getting severer as the lasing wavelength becomes shorter. The UVSOR-FEL had been originally scheduled to be shutdown by 1996 because another undulator project for spectroscopic studies with circular polarized photon would take the FEL`s place. According to suggestion of the insertion device group of the SPring-8, we have designed a helical undulator that is able to vary degree and direction of the polarization easily. In addition, the undulator can be converted into a helical OK by replacing magnets at the center part of undulator in order to coexist with further FEL experiments. Using a calculated magnetic field for magnet configurations of the OK mode, the radiation spectrum at wide wavelength range was simulated by a Fourier transform of Lienard-Wiechert potentials. As a matter of course, some higher harmonics are radiated on the off-axis angle. However it was found out that the higher harmonics is almost negligible as far as inside a solid angle of the Gaussian laser mode. Moreover the gain at the UV region of 250 nm is expected to be much higher than our present FEL because of high brilliant fundamental radiation. The calculated spatial distribution of higher harmonics and the estimated instantaneous gain is presented. Advantages of the helical OK for SRFEL will be discussed in view of our experience, and a possibility of application two-color experiment with SR will be also mentioned.

  19. Wake monochromator in asymmetric and symmetric Bragg and Laue geometry for self-seeding the European X-ray FEL

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni; Serkez, Svitozar; Tolkiehn, Martin

    2013-01-01

    We discuss the use of self-seeding schemes with wake monochromators to produce TW power, fully coherent pulses for applications at the dedicated bio-imaging bealine at the European X-ray FEL, a concept for an upgrade of the facility beyond the baseline previously proposed by the authors. We exploit the asymmetric and symmetric Bragg and Laue reflections (sigma polarization) in diamond crystal. Optimization of the bio-imaging beamline is performed with extensive start-to-end simulations, which also take into account effects such as the spatio-temporal coupling caused by the wake monochromator. The spatial shift is maximal in the range for small Bragg angles. A geometry with Bragg angles close to pi/2 would be a more advantageous option from this viewpoint, albeit with decrease of the spectral tunability. We show that it will be possible to cover the photon energy range from 3 keV to 13 keV by using four different planes of the same crystal with one rotational degree of freedom.

  20. Wake monochromator in asymmetric and symmetric Bragg and Laue geometry for self-seeding the European X-ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni; Serkez, Svitozar; Tolkiehn, Martin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-01-15

    We discuss the use of self-seeding schemes with wake monochromators to produce TW power, fully coherent pulses for applications at the dedicated bio-imaging beamline at the European X-ray FEL, a concept for an upgrade of the facility beyond the baseline previously proposed by the authors. We exploit the asymmetric and symmetric Bragg and Laue reflections (sigma polarization) in diamond crystal. Optimization of the bio-imaging beamline is performed with extensive start-to-end simulations, which also take into account effects such as the spatio-temporal coupling caused by the wake monochromator. The spatial shift is maximal in the range for small Bragg angles. A geometry with Bragg angles close to {pi}/2 would be a more advantageous option from this viewpoint, albeit with decrease of the spectral tunability. We show that it will be possible to cover the photon energy range from 3 keV to 13 keV by using four different planes of the same crystal with one rotational degree of freedom.

  1. A Fast Algorithm for Finding Point Sources in the Fermi Data Stream: FermiFAST

    CERN Document Server

    Ashathaman, Asha; Heyl, Jeremy S

    2016-01-01

    This paper presents a new and efficient algorithm for finding point sources in the photon event data stream from the Fermi Gamma-Ray Space Telescope. It can rapidly construct about most significant half of the Fermi Third Point Source catalogue (3FGL) with nearly 80% purity from the four years of data used to construct the catalogue. If a higher purity sample is desirable, one can achieve a sample that includes the most significant third of the Fermi 3FGL with only five percent of the sources unassociated with Fermi sources. Outside the galaxy plane, the contamination is essentially negligible. This software allows for rapid exploration of the Fermi data, simulation of the source detection to calculate the selection function of various sources and the errors in the obtained parameters of the sources detected.

  2. Upgrading Fermi Without Traveling to Space

    Science.gov (United States)

    Kohler, Susanna

    2016-02-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has received an upgrade that increased its sensitivity by a whopping 40% and nobody had to travel to space to make it happen! The difference instead stems from remarkable improvement to the software used to analyze Fermi-LATs data, and it has resulted in a new high-energy map of our sky.Animation (click to watch!) comparing the Pass 7 to the Pass 8 Fermi-LAT analysis, in a region in the constellation Carina. Pass 8 provides more accurate directions for incoming gamma rays, so more of them fall closer to their sources, creating taller spikes and a sharper image. [NASA/DOE/Fermi LAT Collaboration]Pass 8Fermi-LAT has been surveying the whole sky since August 2008. It detects gamma-ray photons by converting them into electron-positron pairs and tracking the paths of these charged particles. But differentiating this signal from the charged cosmic rays that also pass through the detector with a flux that can be 10,000 times larger! is a challenging process. Making this distinction and rebuilding the path of the original gamma ray relies on complex analysis software.Pass 8 is a complete reprocessing of all data collected by Fermi-LAT. The software has gone through many revisions before now, but this is the first revision that has taken into account all of the experience that the Fermi team has gained operating the LAT in its orbital environment.The improvements made in Pass 8 include better background rejection of misclassified charged particles, improvements to the point spread function and effective area of the detector, and an extension of the effective energy range from below 100 MeV to beyond a few hundred GeV. The changes made in Pass 8 have increased the sensitivity of Fermi-LAT by an astonishing 40%.Map of the High-Energy SkySky map of the sources in the 2FHL catalog, classified by their most likely association. Click for a better look! [Ackermann et al. 2016]The first result from the

  3. Critical issues for high-power FEL based on microtron recuperator/electron out-coupling scheme

    Science.gov (United States)

    Vinokurov, Nikolai A.; Zholents, Alexander A.; Fawley, William M.; Kim, Kwang J.

    1997-05-01

    The FELs based on the rf accelerator-recuperator and the electron outcoupling is promising for obtaining average output power of hundreds of kilowatts. We present basic considerations for the system stability and performance optimization for this scheme.

  4. S2E simulation of an ERL-based high-power EUV-FEL source for lithography

    Science.gov (United States)

    Nakamura, N.; Kato, R.; Miyajima, T.; Shimada, M.; Hotei, T.; Hajima, R.

    2017-07-01

    Energy recovery linac (ERL) based extreme ultraviolet (EUV) free electron lasers (FELs) are candidates of a next-generation high-power EUV source for lithography. An ERL-based EUV FEL source has been designed in order to demonstrate the feasibility of generating a 10-kW class EUV power. Start-to-End (S2E) simulation including the injection beam optimization, bunch compression, FEL lasing and bunch decompression is performed for the designed EUV source. As a result it is demonstrated that the EUV FEL can produce high power more than 10 kW at 10 mA and that the electron beam can be well transported throughout the EUV source without beam loss.

  5. Recommissioning of Duke Storage Ring with a HOM-Damped RF Cavity and a New Straight Section Lattice for FELs

    CERN Document Server

    Wu, Y K; Emamian, Mark; Faircloth, Joe; Gustavsson, J; Hartman, Steven M; Howell, C; Johnson, M; Li, Jingyi; Mikhailov, Stepan; Oakeley, Owen; Patterson, J; Pentico, Maurice; Popov, Victor; Rathbone, V; Swift, Gary; Wallace, Patrick W; Wang, Ping

    2005-01-01

    The Duke FEL lab operates a unique UV/VUV storage ring FEL and an FEL driven, nearly monochromatic, highly polarized, high intensity Compton gamma-ray source. The Duke storage ring light source is undergoing several phases of upgrade in order to significantly improve light source capabilities and performance. The 2004 phase included an upgrade of the RF system with a high-order mode damped RF cavity and a new 34 meter long straight section lattice to host new FEL wigglers in the next phase. This upgrade was completed in August 2004 and storage ring and light source commissioning were completed in November 2004. This paper will provide an overview of this upgrade project and report our commissioning experience of the storage ring and light sources.

  6. Operation of the European FEL at ELETTRA Below 190 nm A Tunable Laser Source for VUV Spectroscopy

    CERN Document Server

    De Ninno, G; Curbis, F; Danailov, M B; Diviacco, B; Marsi, M; Trovò, M

    2005-01-01

    Thanks to an intensive technological effort in the framework of the EEC Contract HPRI CT-2001-50025 (EUFELE), the European FEL at ELETTRA was able to break the previous record for the shortest wavelength of an FEL oscillator. Novel solutions were adopted for multilayer mirrors to allow FEL operation in the wavelength region between 160 and 190 nm, which is one of the main targets of the project. The characteristics of the FEL pulses measured at 176 nm (spectral profiles, high intensity, meV bandpass, MHz repetition rate) make it a competitive light source for spectroscopy, in particular for fluorescence studies in the VUV spectral range. Proof of principle experiments have been performed on different types of silica glasses, yielding information on the mechanisms of light absorption in this material.

  7. Monte Carlo Mean Field Treatment of Microbunching Instability in the FERMI@Elettra First Bunch Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Bassi, G.; /Liverpool U. /Cockroft Inst.; Ellison, J.A.; Heinemann, K.; /New Mexico U.; Warnock, R.; /SLAC

    2009-05-07

    Bunch compressors, designed to increase the peak current, can lead to a microbunching instability with detrimental effects on the beam quality. This is a major concern for free electron lasers (FELs) where very bright electron beams are required, i.e. beams with low emittance and energy spread. In this paper, we apply our self-consistent, parallel solver to study the microbunching instability in the first bunch compressor system of FERMI{at}Elettra. Our basic model is a 2D Vlasov-Maxwell system. We treat the beam evolution through a bunch compressor using our Monte Carlo mean field approximation. We randomly generate N points from an initial phase space density. We then calculate the charge density using a smooth density estimation procedure, from statistics, based on Fourier series. The electric and magnetic fields are calculated from the smooth charge/current density using a novel field formula that avoids singularities by using the retarded time as a variable of integration. The points are then moved forward in small time steps using the beam frame equations of motion, with the fields frozen during a time step, and a new charge density is determined using our density estimation procedure. We try to choose N large enough so that the charge density is a good approximation to the density that would be obtained from solving the 2D Vlasov-Maxwell system exactly. We call this method the Monte Carlo Particle (MCP) method.

  8. Beyond the 2nd Fermi Pulsar Catalog

    CERN Document Server

    Hou, Xian; Reposeur, Thierry; Rousseau, Romain

    2013-01-01

    Over thirteen times more gamma-ray pulsars have now been studied with the Large Area Telescope on NASA's Fermi satellite than the ten seen with the Compton Gamma-Ray Observatory in the nineteen-nineties. The large sample is diverse, allowing better understanding both of the pulsars themselves and of their roles in various cosmic processes. Here we explore the prospects for even more gamma-ray pulsars as Fermi enters the 2nd half of its nominal ten-year mission. New pulsars will naturally tend to be fainter than the first ones discovered. Some of them will have unusual characteristics compared to the current population, which may help discriminate between models. We illustrate a vision of the future with a sample of six pulsars discovered after the 2nd Fermi Pulsar Catalog was written.

  9. Fermi's Paradox - The Last Challenge for Copernicanism?

    CERN Document Server

    Cirkovic, Milan M

    2009-01-01

    We review Fermi's paradox (or the "Great Silence" problem), not only arguably the oldest and crucial problem for the Search for ExtraTerrestrial Intelligence (SETI), but also a conundrum of profound scientific, philosophical and cultural importance. By a simple analysis of observation selection effects, the correct resolution of Fermi's paradox is certain to tell us something about the future of humanity. Already a more than three quarters of a century old puzzle - and a quarter of century since the last major review paper in the field by G. David Brin - Fermi's paradox has generated many ingenious discussions and hypotheses. We analyze the often tacit methodological assumptions built into various answers to this puzzle and attempt a new classification of the numerous solutions proposed in an already huge literature on the subject. Finally, we consider the ramifications of various classes of hypotheses for the practical SETI projects. Somewhat paradoxically, it seems that the class of (neo)catastrophic hypoth...

  10. Pairing in a dry Fermi sea.

    Science.gov (United States)

    Maier, T A; Staar, P; Mishra, V; Chatterjee, U; Campuzano, J C; Scalapino, D J

    2016-06-17

    In the traditional Bardeen-Cooper-Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and -k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will eventually lead to a pairing instability. However, in the pseudogap regime of the cuprate superconductors, where parts of the Fermi surface are destroyed, this log singularity is suppressed, raising the question of how pairing occurs in the absence of a Fermi sea. Here we report Hubbard model numerical results and the analysis of angular-resolved photoemission experiments on a cuprate superconductor. In contrast to the traditional theory, we find that in the pseudogap regime the pairing instability arises from an increase in the strength of the spin-fluctuation pairing interaction as the temperature decreases rather than the Cooper log instability.

  11. Dark lump excitations in superfluid Fermi gases

    Institute of Scientific and Technical Information of China (English)

    Xu Yan-Xia; Duan Wen-Shan

    2012-01-01

    We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases.A Kadomtsev Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen-Cooper-Schrieffer (BCS) regime,Bose-Einstein condensate (BEC) regime,and unitarity regime.Onelump solution as well as one-line soliton solutions for the KPI equation are obtained,and two-line soliton solutions with the same amplitude are also studied in the limited cases.The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity.

  12. Pseudogap-generated a coexistence of Fermi arcs and Fermi pockets in cuprate superconductors

    Science.gov (United States)

    Zhao, Huaisong; Gao, Deheng; Feng, Shiping

    2017-03-01

    One of the most intriguing puzzle is why there is a coexistence of Fermi arcs and Fermi pockets in the pseudogap phase of cuprate superconductors? This puzzle is calling for an explanation. Based on the t - J model in the fermion-spin representation, the coexistence of the Fermi arcs and Fermi pockets in cuprate superconductors is studied by taking into account the pseudogap effect. It is shown that the pseudogap induces an energy band splitting, and then the poles of the electron Green's function at zero energy form two contours in momentum space, however, the electron spectral weight on these two contours around the antinodal region is gapped out by the pseudogap, leaving behind the low-energy electron spectral weight only located at the disconnected segments around the nodal region. In particular, the tips of these disconnected segments converge on the hot spots to form the closed Fermi pockets, generating a coexistence of the Fermi arcs and Fermi pockets. Moreover, the single-particle coherent weight is directly related to the pseudogap, and grows linearly with doping. The calculated result of the overall dispersion of the electron excitations is in qualitative agreement with the experimental data. The theory also predicts that the pseudogap-induced peak-dip-hump structure in the electron spectrum is absent from the hot-spot directions.

  13. 17th international free electron laser conference and 2nd international FEL users` workshop. Program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    This workshop and conference were held together to enhance the interaction between FEL builders and users. Current topics of interest in FEL research form the basis for the oral presentations. The program for the User`s workshop was developed in a similar manner. Storage rings, linear accelerators, materials research and applications are all considered topics. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  14. Statistical properties of the radiation from SASE FEL operating in a post-saturation regime with and without undulator tapering

    CERN Document Server

    Schneidmiller, E A

    2015-01-01

    We describe statistical and coherence properties of the radiation from x-ray free electron lasers (XFEL) operating in the post-saturation regime. We consider practical case of the SASE3 FEL at the European XFEL. We perform comparison of the main characteristics of the X-ray FEL operating in the post-saturation regime with and without undulator tapering: efficiency, coherence time and degree of transverse coherence.

  15. Temporal characterization of FEL micropulses as function of cavity length detuning using frequency-resolved optical gating

    Energy Technology Data Exchange (ETDEWEB)

    Richman, B.A. [Stanford Univ., CA (United States); DeLong, K.W.; Trebino, R. [Sandia National Lab., Livermore, CA (United States)

    1995-12-31

    Results of frequency resolved optical gating (FROG) measurements on the Stanford mid-IR FEL system show the effect of FEL cavity length detuning on the micropulse temporal structure. The FROG technique enables the acquisition of complete and uniquely invertible amplitude and phase temporal dependence of optical pulses. Unambiguous phase and amplitude profiles are recovered from the data. The optical pulses are nearly transform limited, and the pulse length increases with cavity length detuning.

  16. Supernova Remnants with Fermi Large Area Telescope

    Directory of Open Access Journals (Sweden)

    Caragiulo M.

    2017-01-01

    Full Text Available The Large Area Telescope (LAT, on-board the Fermi satellite, proved to be, after 8 years of data taking, an excellent instrument to detect and observe Supernova Remnants (SNRs in a range of energies running from few hundred MeV up to few hundred GeV. It provides essential information on physical processes that occur at the source, involving both accelerated leptons and hadrons, in order to understand the mechanisms responsible for the primary Cosmic Ray (CR acceleration. We show the latest results in the observation of Galactic SNRs by Fermi-LAT.

  17. Clustering in the nuclear Fermi liquid

    CERN Document Server

    Ebran, J -P; Niksic, T; Vretenar, D

    2012-01-01

    We analyze the emergence of various structures in nucleonic matter, such as crystal, clusters, liquid drops and haloes. The formation of clusters indicates that nuclei behave like a Fermi liquid close to the liquid to solid transition. The relevant parameter is the ratio of the dispersion of the single-nucleon wave functions in the nucleus to the inter-nucleon distance. We also discuss the relationship between cluster states in nuclei and the pasta phase in the crust of neutron stars, as a transitional state between a Fermi liquid and a crystal. Haloes and clusters exhibit opposite features with respect to nucleonic localization.

  18. The Mirage of the Fermi Scale

    DEFF Research Database (Denmark)

    Antipin, Oleg; Sannino, Francesco; Tuominen, Kimmo

    2013-01-01

    The discovery of a light Higgs boson at LHC may be suggesting that we need to revise our model building paradigms to understand the origin of the weak scale. We explore the possibility that the Fermi scale is not fundamental but rather a derived one, i.e. a low energy mirage. We show that this sc......The discovery of a light Higgs boson at LHC may be suggesting that we need to revise our model building paradigms to understand the origin of the weak scale. We explore the possibility that the Fermi scale is not fundamental but rather a derived one, i.e. a low energy mirage. We show...

  19. MASTER: OT detection during Fermi trigger inspection

    Science.gov (United States)

    Popova, E.; Lipunov, V.; Buckley, D.; Gorbovskoy, E.; Tiurina, N.; Balanutsa, P.; Kuznetsov, A.; Kornilov, V.; Chazov, V.; Vlasenko, D.; Vladimirov, V.; Gress, O.; Ivanov, K.; Potter, S.; Gabovich, A.

    2016-11-01

    During inspection of Fermi trigger 501261070 ( (Ra,Dec)=47.190,-47.210; GRB_ERROR_radius=3.27deg, GRB_TIME=2016/11/19 15:11:06.40UT http://gcn.gsfc.nasa.gov/other/501261070.fermi ) MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 03h 22m 52.70s -48d 29m 10.9s on 2016-11-19 21:17:17.878UT with unfiltered m_OT=17.8 (mlim=19.7).

  20. Scattering resonances in a degenerate Fermi gas

    DEFF Research Database (Denmark)

    Challis, Katharine; Nygaard, Nicolai; Mølmer, Klaus

    2009-01-01

    We consider elastic single-particle scattering from a one-dimensional trapped two-component superfluid Fermi gas when the incoming projectile particle is identical to one of the confined species. Our theoretical treatment is based on the Hartree-Fock ground state of the trapped gas and a configur......We consider elastic single-particle scattering from a one-dimensional trapped two-component superfluid Fermi gas when the incoming projectile particle is identical to one of the confined species. Our theoretical treatment is based on the Hartree-Fock ground state of the trapped gas...

  1. Itinerant Ferromagnetism in Ultracold Fermi Gases

    DEFF Research Database (Denmark)

    Heiselberg, Henning

    2012-01-01

    Itinerant ferromagnetism in cold Fermi gases with repulsive interactions is studied applying the Jastrow-Slater approximation generalized to finite polarization and temperature. For two components at zero temperature a second order transition is found at akF ≃ 0.90 compatible with QMC. Thermodyna......Itinerant ferromagnetism in cold Fermi gases with repulsive interactions is studied applying the Jastrow-Slater approximation generalized to finite polarization and temperature. For two components at zero temperature a second order transition is found at akF ≃ 0.90 compatible with QMC...

  2. 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).

  3. 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).

  4. Construction and Commissioning of PAL-XFEL Facility

    Directory of Open Access Journals (Sweden)

    In Soo Ko

    2017-05-01

    Full Text Available The construction of Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL, a 0.1-nm hard X-ray free-electron laser (FEL facility based on a 10-GeV S-band linear accelerator (LINAC, is achieved in Pohang, Korea by the end of 2016. The construction of the 1.11 km-long building was completed by the end of 2014, and the installation of the 10-GeV LINAC and undulators started in January 2015. The installation of the 10-GeV LINAC, together with the undulators and beamlines, was completed by the end of 2015. The commissioning began in April 2016, and the first lasing of the hard X-ray FEL line was achieved on 14 June 2016. The progress of the PAL-XFEL construction and its commission are reported here.

  5. Detailed numerical studies of space charge effects in an FEL RF gun

    CERN Document Server

    Cee, R R; Setzer, S; Weiland, T; Novokhatski, A

    2002-01-01

    The production of short bunches with low emittance is a key issue for the successful operation of an SASE-FEL as proposed by the TESLA collaboration (TESLA Technical design report, DESY 2001-011, Hamburg, 2001). In this paper we present the results of detailed MAFIA TS-2 (CST GmbH, Buedinger Strasse 2a, D-64289 Darmstadt) simulations for the FEL RF-gun revealing the main physical effects leading to emittance growth. The simulations prove that the transverse emittance growth can mainly be observed close to the cathode area. This is caused by the non-linear space charge forces acting inside the bunch during the injection process. For the application of an emittance compensation scheme (Nucl. Instr. and Meth. 285 (1989) 313) the slice emittance is of significant importance. Therefore, a wide range of parameters for the photo cathode laser has been investigated in order to find an appropriate operation point.

  6. Design Concept for a Compact ERL to Drive a VUV/Soft X-Ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Christopher Tennant ,David Douglas

    2011-03-01

    We explore possible upgrades of the existing Jefferson Laboratory IR/UV FEL driver to higher electron beam energy and shorter wavelength through use of multipass recirculation to drive an amplifier FEL. The system would require beam energy at the wiggler of 600 MeV with 1 mA of average current. The system must generate a high brightness beam, configure it appropriately, and preserve beam quality through the acceleration cycle ? including multiple recirculations ? and appropriately manage the phase space during energy recovery. The paper will discuss preliminary design analysis of the longitudinal match, space charge effects in the linac, and recirculator design issues, including the potential for the microbunching instability. A design concept for the low energy recirculator and an emittance preserving lattice solution will be presented.

  7. An experimental study of an FEL oscillator with a linear taper

    CERN Document Server

    Benson, S; Neil, G R

    2001-01-01

    Motivated by the work of Saldin, Schneidmiller and Yurkov, we have measured the detuning curve widths, spectral characteristics, efficiency, and energy spread as a function of the taper for low and high Q resonators in the IR Demo FEL at Jefferson Lab. Both positive and negative tapers were used. Gain and frequency agreed surprisingly well with the predictions of a single mode theory. The efficiency agreed reasonably well for a negative taper with a high Q resonator but disagreed for lower Q values both due to the large slippage parameter and the non-ideal resonator Q. We saw better efficiency for a negative taper than for the same positive taper. The energy spread induced in the beam, normalized to the efficiency is larger for the positive taper than for the corresponding negative taper. This indicates that a negative taper is preferred over a positive taper in an energy recovery FEL.

  8. An experimental study of an FEL oscillator with a linear taper

    Science.gov (United States)

    Benson, S.; Gubeli, J.; Neil, G. R.

    2001-12-01

    Motivated by the work of Saldin, Schneidmiller and Yurkov, we have measured the detuning curve widths, spectral characteristics, efficiency, and energy spread as a function of the taper for low and high Q resonators in the IR Demo FEL at Jefferson Lab. Both positive and negative tapers were used. Gain and frequency agreed surprisingly well with the predictions of a single mode theory. The efficiency agreed reasonably well for a negative taper with a high Q resonator but disagreed for lower Q values both due to the large slippage parameter and the non-ideal resonator Q. We saw better efficiency for a negative taper than for the same positive taper. The energy spread induced in the beam, normalized to the efficiency is larger for the positive taper than for the corresponding negative taper. This indicates that a negative taper is preferred over a positive taper in an energy recovery FEL.

  9. BEAM OPTIMIZATION STUDY FOR AN X-RAY FEL OSCILLATOR AT THE LCLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Weilun; Huang, S.; Liu, K.X.; Huang, Z; Ding, Y.; Maxwell, T.J.; Kim, K.-J.

    2016-06-01

    The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.

  10. L- and K-shell emission from X-FEL heated iron

    Science.gov (United States)

    Heimann, Philip; Hansen, Stephanie; Loisel, Guillaume; Bailey, James; Gamboa, Eliseo; Glenzer, Siegfried; Mancini, Roberto; Saunders, Alison; Falcone, Roger; Galtier, Eric

    2016-10-01

    At the LCLS MEC instrument, a tightly focused X-ray FEL beam is used to isochorically heat thin iron samples. Two compound refractive lenses produce a focus estimated to be 0.5 microns (FWHM). The L-emission from the hot, solid-density samples is measured by RAP(001) crystal and grating spectrometers. In addition, the K-emission is observed by a Ge(111) crystal spectrometer. The L-shell emission from iron, which is initially photoionized by the X-ray FEL, tests recent measurements indicating higher-than-predicted broadening of the L-shell emission lines. Heating at 7 and 9.2 keV photon energies compares different heating mechanisms.

  11. A non-conventional ERL configuration for high-power EUV FELs

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M., E-mail: mventurini@lbl.gov; Penn, G.

    2015-09-21

    We show that a standard Linac configuration (consisting of accelerating sections, linearizing section, and magnetic chicane compressor) currently used in drivers for single-pass EUV/x-ray FELs is compatible with energy recovery, provided that certain timing constraints are met. By circulating the spent, rather than the fresh beam as in a conventional high-power ERL FEL design, the beam brightness can be more easily preserved thus facilitating lasing at short wavelength. As in a conventional ERL, the proposed design allows for energy-spread compression, enabling low-energy beam dumping and high energy-recovery efficiency. Results from numerical simulations presented in this paper show that this configuration could, in principle, support the generation of multi-kW average radiation power required for high-volume production EUV lithography.

  12. Transverse Emittance Measurements In High-power Fir Fel Energy-recovery Linac

    CERN Document Server

    Bolotin, V P; Matveenko, A N; Shevchenko, O A; Vinokurov, N A

    2004-01-01

    50 MeV accelerator-recirculator of Siberian Center for Photochemical Research has been designed to drive the FIR FEL with an average power of up to 10 kW in the wavelengths region from 5 to 200 μm. The first stage with the beam energy of 14 MeV was put into operation and laser power of about 200 W on 150 μm was achieved recently [1]. Transverse emittance measurements are carried out online in a number of locations along the beam-line. OTR screens and video-cameras are used to capture the beam shape images, video signal is digitized by a frame grabber and the pictures are processed further. Online measurements allow the accelerator parameters to be optimized to minimize the emittance growth, which is essential to the FEL operation. The transverse emittance measurements system and data processing techniques are presented in this paper.

  13. Measurements of nonlinear harmonic generation at the Advanced Photon Source's SASE FEL

    CERN Document Server

    Biedron, S G; Borland, M; Dejus, Roger J; Den Hartog, P K; Erdmann, M; Fawley, W M; Freund, H P; Gluskin, E; Huang, Z; Kim, K J; Lewellen, J W; Li, Y; Lumpkin, Alex H; Milton, S V; Moog, E; Nassiri, A; Sajaev, Vadim; Wiemerslage, G; Yang, B X

    2002-01-01

    SASE saturation was recently achieved at the Advanced Photon Source's SASE FEL in the low-energy undulator test line at 530 nm and 385 nm. The electron beam microbunching becomes more and more prominent until saturation is achieved. This bunching causes nonlinear harmonic emission that extends the usefulness of a SASE system in achieving shorter FEL wavelengths for the same electron beam energy. We have investigated the intensity of the fundamental and second harmonic undulator radiation as a function of distance along the undulator line and present the experimental results and compare them to numerical simulations. In addition, we have measured the single-shot second harmonic spectra as well as the simultaneous fundamental and second harmonic spectra and present the experimental results.

  14. Simulation of planar FEL-amplifier with tape relativistic electron beam

    CERN Document Server

    Ginzburg, N S; Peskov, N Yu; Arzhannikov, A V; Sinitskij, S L

    2001-01-01

    The simulation of the planar microwave (4 mm) amplifier on the basis of the powerful laser on free electrons (FEL- amplifier) is carried out. The tape relativistic electron beam with the energy up to 1 MeV and operating current up to 2 kA is formed by the Y-3 accelerators. The complete nonaveraging system of the self-consistent equations describing the process of interaction of the particles, moving in the plane ondulator field is obtained. Thereafter the averaging of the above-mentioned equations was carried out and the linear and nonlinear stages of the amplification process were studied. The additional simulation of the FEL-amplifier is carried out on the basis of the two-dimensional version of the KARAT PIC-code. It is shown that the applied approaches give sufficiently close results

  15. Design considerations for the coherent radiator, FEL, in the MAX IV proposal

    CERN Document Server

    Werin, Sverker; Brandin, Mathias; Eriksson, Mikael; Hansen, T N; Larsson, Jörgen; Lindgren, L J; Tarawneh, Hamed

    2004-01-01

    The MAX IV proposal is a project for the next Swedish synchrotron radiation source. Currently a design study is produced with funding from the Swedish research council (VR). One half of the project will be a double storage ring (at 3 and 1.5 GeV respectively) but the other half will be a coherent radiator, FEL, based on the 3 GeV injector. The basic FEL solution will consist of a normal conducting linac at 3 GeV which feeds three seeded cascaded optical klystrons and a radiator undulator to produce radiation down to 1.5-3 nm at GW powers. To assure synchronisation the gun laser and the seed laser share initial laser and amplifier. This basic system can be enhanced in various ways which will be discussed .

  16. First operation of a powerful FEL with two-dimensional distributed feedback

    CERN Document Server

    Agarin, N V; Bobylev, V B; Ginzburg, N S; Ivanenko, V G; Kalinin, P V; Kuznetsov, S A; Peskov, N Yu; Sergeev, A S; Sinitsky, S L; Stepanov, V D

    2000-01-01

    A W-band (75 GHz) FEL of planar geometry driven by a sheet electron beam was realised using the pulse accelerator ELMI (0.8 MeV/3 kA/5 mu s). To provide the spatial coherence of radiation from different parts of the electron beam with a cross-section of 0.4x12 cm two-dimensional distributed feedback systems have been employed using a 2-D Bragg resonator of planar geometry. The resonator consisted of two 2-D Bragg reflectors separated by a regular waveguide section. The total energy in the microwave pulse of microsecond duration was 100 J corresponding to a power of approx 100 MW. The main component of the FEL radiation spectrum was at 75 GHz that corresponded to the zone of effective Bragg reflection found from 'cold' microwave testing of the resonator. The experimental data compared well with the results of theoretical analysis.

  17. JLAMP: AN AMPLIFIER-BASED FEL IN THE JLAB SRF ERL DRIVER

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Jordan; Stephen V. Benson; David Douglas; Pavel Evtushenko; Carlos Hernandez-Garcia; George R. Neil

    2007-06-13

    Notional designs for energy-recovering linac (“ERL”) -driven high average power free electron lasers (“FEL”s) often invoke amplifier-based architectures. To date, however, amplifier FELs have been limited in average power output to values several orders of magnitude lower than those demonstrated in optical-resonator based systems; this is due at least in part to the limited electron beam powers available from their driver accelerators. In order to directly contrast the performance available from amplifiers to that provided by high-power cavity-based resonators, we have developed a scheme to test an amplifier FEL in the JLab SRF ERL driver. We describe an accelerator system design that can seamlessly and non-invasively integrate a 10 m wiggler into the existing system and which provides, at least in principle, performance that would support high-efficiency lasing in an amplifier configuration. Details of the design and an accelerator performance analysis will be presented

  18. A status report on the development of a high power UV and IR FEL at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.V.; Bisognano, J.; Bohn, C. [and others

    1996-08-01

    Previously the authors presented a design for a kilowatt demonstration industrial UVFEL. Progress has been made in resolving several design issues identified in that work. More exact simulations of the injector have resulted in a better estimate of the injector performance. A more compact lattice has been designed meeting the design requirements for the UV FEL, and a new design point has been studied which greatly increases the threshold for longitudinal instabilities. A stability analysis of the RF control system has found that only minor modifications from the existing CEBAF controls will be necessary to allow them to be used with a high current, energy-recovery accelerator. Designs for the optical cavity length and figure control systems have been conceptualized and a model of the corner-cube resonator is being built and tested. Finally, three-dimensional simulations of the FEL have been carried out which show that the laser should exceed its minimum design goals for average power.

  19. Development of photon beam diagnostics for VUV radiation from a SASE FEL

    CERN Document Server

    Treusch, R; Xu, W; Jastrow, U; Hahn, U; Bittner, L; Feldhaus, J

    2000-01-01

    For the proof-of-principle experiment of self-amplified spontaneous emission (SASE) at short wavelengths on the VUV FEL at DESY a multi-facetted photon beam diagnostics experiment has been developed employing new detection concepts to measure all SASE specific properties on a single pulse basis. The present setup includes instrumentation for the measurement of the energy and the angular and spectral distribution of individual photon pulses. Different types of photon detectors such as PtSi-photodiodes and fast thermoelectric detectors based on YBaCuO-films are used to cover some five orders of magnitude of intensity from the level of spontaneous emission to FEL radiation at saturation. A 1 m normal incidence monochromator in combination with a fast intensified CCD camera allows to select single photon pulses and to record the full spectrum at high resolution to resolve the fine structure due to the start-up from noise.

  20. Tapering studies for Terawatt level X-ray FELs with a superconducting undulator

    CERN Document Server

    Emma, Claudio; Emma, Paul; Huang, Zhirong; Pellegrini, Claudio

    2015-01-01

    We study the tapering optimization scheme for a short period, less than two cm, superconducting undulator, and show that it can generate 4 keV X-ray pulses with peak power in excess of 1 terawatt, using LCLS electron beam parameters. We study the e?ect of undulator module length relative to the FEL gain length for continous and step-wise taper pro?les. For the optimal section length of 1.5m we study the evolution of the FEL process for two di?erent superconducting technologies NbTi and Nb3Sn. We discuss the major factors limiting the maximum output power, particle detrapping around the saturation location and time dependent detrapping due to generation and ampli?cation of sideband modes.

  1. Transient Mirror Heating Theory and Experiment in the Jefferson Lab IR Demo FEL

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.; Michelle D. Shinn.; Neil, G.R.

    2001-01-01

    During commissioning of the IR Demo FEL at Jefferson Lab, we noticed that the FEL exhibited a rapid power drop with time when the first set of 3 mu-m mirrors was used. Thought the rate of power drop was unexpected, it was thought that it could be due to a distortion of the mirrors during a time short compared to a the thermal diffusion time. This transient distortion might affect the laser more than the steady state distortion. This paper presents some analysis of the transient mirror heating problem and some recent experimental results using different mirror substrates and coatings. It is found that the behavior of the first mirror set cannot be reconciled with the observed power fall-off if a linear absorption is assumed. The power drop in more recent experiments is consistent with linear thermal analysis. No anomalous transient effects are seen.

  2. Intense inverse compton {gamma}-ray source from Duke storage ring FEL

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)

    1995-12-31

    We suggest using FEL intracavity power in the Duke storage ring fortrays production via Inverse Compton Backscattering (ICB). The OK-4 FEL driven by the Duke storage ring will tens of watts of average lasing power in the UV/VUV range. Average intracavity power will be in kilowatt range and can be used to pump ICB source. The {gamma}-rays with maximum energy from 40 MeV to 200 MeV with intensity of 0.1-5 10{sup 10}{gamma} per second can be generated. In this paper we present expected parameters of {gamma}-ray beam parameters including its intensity and distribution. We discuss influence of e-beam parameters on collimated {gamma}-rays spectrum and optimization of photon-electron interaction point.

  3. Towards possible opportunities in nuclear materials science and technology at an X-ray free electron laser research facility

    Science.gov (United States)

    Froideval, A.; Badillo, A.; Bertsch, J.; Churakov, S.; Dähn, R.; Degueldre, C.; Lind, T.; Paladino, D.; Patterson, B. D.

    2011-09-01

    Spectroscopy and imaging of condensed matter have benefited greatly from the availability of intense X-ray beams from synchrotron sources, both in terms of spatial resolution and of elemental specificity. The advent of the X-ray free electron laser (X-ray FEL) provides the additional features of ultra-short pulses and high transverse coherence, which greatly expand possibilities to study dynamic processes and to image non-crystalline materials. The proposed SwissFEL facility at the Paul Scherrer Institute is one of at present four X-ray FEL projects worldwide and is scheduled to go into operation in the year 2017. This article describes a selection of problems in nuclear materials science and technology that would directly benefit from this and similar X-ray FEL sources. X-ray FEL-based experiments are proposed to be conducted on nuclear energy-related materials using single-shot X-ray spectroscopy, coherent X-ray scattering and/or X-ray photon correlation spectroscopy in order to address relevant scientific questions such as the evolution in time of the irradiation-induced damage processes, the deformation processes in nuclear materials, the ion diffusion processes in the barrier systems of geological repositories, the boiling heat transfer in nuclear reactors, as well as the structural characterization of graphite dust in advanced nuclear reactors and clay colloid aggregates in the groundwater near a radioactive waste repository.

  4. Longitudinal Space Charge Effects in the JLAB IR FEL SRF Linac

    CERN Document Server

    Hernandez-Garcia, Carlos; Behre, Chris; Benson, S V; Herman-Biallas, George; Boyce, James; Douglas, David; Dylla, Fred; Evans, Richard; Grippo, A; Gubeli, Joe; Hardy, David; Jordan, Kevin; Merminga, Lia; Neil, George; Preble, Joe; Shinn, Michelle D; Siggins, Tim; Walker, Richard; Williams, Gwyn; Yunn, Byung; Zhang, Shukui

    2004-01-01

    Observations of energy spread asymmetry when operating the Linac on either side of crest and longitudinal emittance growth have been confirmed by extending PARMELA simulations from the injector to the end of the first SRF Linac module. The asymmetry can be explained by the interaction of the accelerating electric field with that from longitudinal space charge effects within the electron bunch. This can be a major limitation to performance in FEL accelerators.

  5. 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)

  6. Condensed matter research using the UCSB FEL. Final technical report, May 1, 1984--January 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    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)

  7. Tailoring the amplification of attosecond pulse through detuned X-ray FEL undulator.

    Science.gov (United States)

    Kumar, Sandeep; Kang, Heung-Sik; Kim, Dong Eon

    2015-02-09

    We demonstrate that the amplification of attosecond pulse in X-ray free electron laser (FEL) undulator can be tailored. The characteristic of the amplification of an isolated attosecond pulse in the FEL undulator is investigated. An isolated 180 attoseconds full width half maximum (FWHM) pulse at 1.25 nm with a spectral bandwidth of 1% is injected into an undulator. The simulation results show that for a direct seeding of 3MW, the seed is amplified to the peak power of 106 GW (40 μJ, an output pulse-width of 383 attoseconds) in the presence of a detuning at FEL resonance condition in 100-m long undulator. We note that the introduction of detuning leads to the better performance compared to the case without detuning: shorter by 15.5% in a pulse-width and higher by 76.6% in an output power. Tapering yields a higher power (116% increases in the output power compared to the case without detuning) but a longer pulse (15.4% longer in the pulse-width). It was observed that ± Δλ(r)/8 (Δλ(r)/λ(r) ~1%) is the maximum degree of detuning, beyond which the amplification becomes poor: lower in the output power and longer in the pulse duration. The minimum power for a seed pulse needs to be higher than 1 MW for the successful amplification of an attosecond pulse at 1.25 nm. Also, the electron beam energy-spread must be less than 0.1% for a suitable propagation of attosecond pulse along the FEL undulator under this study.

  8. Status of RF system for the JAERI energy-recovery linac FEL

    Science.gov (United States)

    Sawamura, Masaru; Nagai, Ryoji

    2006-02-01

    The two types of the RF sources are used for the JAERI ERL-FEL. One is an all-solid state amplifier and the other is an inductive output tube (IOT). There are advantages of little failure and wide bandwidth for the all-solid state amplifier, low cost and high efficiency for IOT. The property of low cost with the IOT is suitable for a large machine like an energy recovery linac (ERL).

  9. Studies of a Linac Driver for a High Repetition Rate X-Ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M.; Corlett, J.; Doolittle, L.; Filippetto, D.; Papadopoulos, C.; Penn, G.; Prosnitz, D.; Qiang, J.; Reinsch, M.; Ryne, R.; Sannibale, F.; Staples, J.; Wells, R.; Wurtele, J.; Zolotorev, M.; Zholents, A.

    2011-06-01

    We report on on-going studies of a superconducting CW linac driver intended to support a high repetition rate FEL operating in the soft x-rays spectrum. We present a pointdesign for a 1.8 GeV machine tuned for 300 pC bunches and delivering low-emittance, low-energy spread beams as needed for the SASE and seeded beamlines.

  10. Nonlinear absorption and transmission properties of Ge, Te and InAs using tuneable IR FEL

    Energy Technology Data Exchange (ETDEWEB)

    Amirmadhi, F.; Becker, K.; Brau, C.A. [Vanderbilt Univ., Nashville, TN (United States)

    1995-12-31

    Nonlinear absorption properties of Ge, Te and InAs are being investigated using the transmission of FEL optical pulses through these semiconductors (z-scan method). Wavelength, intensity and macropulse dependence are used to differentiate between two-photon and free-carrier absorption properties of these materials. Macropulse dependence is resolved by using a Pockles Cell to chop the 4-{mu}s macropulse down to 100 ns. Results of these experiments will be presented and discussed.

  11. Dynamical aspects on FEL interaction in single passage and storage ring devices

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G.; Renieri, A. [ENEA, Frascati (Italy)

    1995-12-31

    The dynamical behaviour of the free-electron lasers is investigated using appropriate scaling relations valid for devices operating in the low and high gain regimes, including saturation. The analysis is applied to both single passage and storage ring configurations. In the latter case the interplay between the interaction of the electron bean with the laser field and with the accelerator environment is investigated. In particular we discuss the effect of FEL interaction on the microwave instability.

  12. Fermi and the Theory of Weak Interactions

    CERN Document Server

    Rajasekaran, G

    2014-01-01

    The history of weak interactions starting with Fermi's creation of the beta decay theory and culminating in its modern avatar in the form of the electroweak gauge theory is described. Discoveries of parity violation, matter-antimatter asymmetry, W and Z bosons and neutrino mass are highlighted.

  13. Fermi surface effects in terbium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, P.

    1976-10-01

    Work is reported which was conducted to test of the relation of the generalized susceptibility (and therefore, the ordering properties) for Tb to the Fermi energy of Tb. In order to properly analyze the data a simple theory was developed to account for the effects on band structure which accompany alloying and attendant lattice size changes. Using this simple theory, the alloys of Tb with Mg are understood as a combination of Fermi energy lowering and of lattice contraction. The tendency of Th to promote the ferromagnetic structure in Th is understood as a combination of the Fermi energy being raised and of the lattice being expanded. The theory was also useful in explaining the interesting behavior of the Tb with Yb alloys which upon preliminary analysis did not seem to follow the theoretical predictions. After consideration of the volume effect, indeed the Tb with Yb alloys showed promotion of the helical structure as predicted. The complicated behavior of the Tb with Yb alloys is a case where the volume and valence effects compete. Results show that the magnetic ordering properties of the rare earths are intimately related to the Fermi surface geometry through the generalized susceptibility.

  14. Fermi detected blazars seen by INTEGRAL

    CERN Document Server

    Beckmann, V; Soldi, S

    2009-01-01

    Multiwavelength observations are essential to constrain physical parameters of the blazars observed by Fermi/LAT. Among the 187 AGN significantly detected in public INTEGRAL data above 20 keV by the imager IBIS/ISGRI, 20 blazars were detected. 15 of these sources allowed significant spectral extraction. They show hard X-ray spectra with an average photon index of 2.1+-0.1 and a hard X-ray luminosity of L(20-100 keV) = 1.3e46 erg/s. 15 of the INTEGRAL blazars are also visible in the first 16 months of the Fermi/LAT data, thus allowing to constrain the inverse Compton branch in these cases. Among others, we analyse the LAT data of four blazars which were not included in the Fermi LAT Bright AGN Sample based on the first 3 months of the mission: QSO B0836+710, H 1426+428, RX J1924.8-2914, and PKS 2149-306. Especially for blazars during bright outbursts, as already observed simultaneously by INTEGRAL and Fermi (e.g. 3C 454.3 and Mrk 421), INTEGRAL provides unique spectral coverage up to several hundred keV. We pr...

  15. Switchable Fermi surface sheets in greigite

    NARCIS (Netherlands)

    Zhang, B.; de Wijs, G. A.; de Groot, R. A.

    2012-01-01

    Greigite (Fe3S4) and magnetite (Fe3O4) are isostructural and isoelectronic ferrimagnets with quite distinct properties. Electronic structure calculations reveal greigite is a normalmetal in contrast to half-metallic magnetite. Greigite shows a complex Fermi surface with a unique influence of

  16. FERMI LARGE AREA TELESCOPE SECOND SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Nolan, P. L.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Abdo, A. A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Antolini, E.; Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Atwood, W. B.; Belfiore, A. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L.; Bellazzini, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d' Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bignami, G. F., E-mail: digel@stanford.edu, E-mail: Gino.Tosti@pg.infn.it, E-mail: jean.ballet@cea.fr, E-mail: tburnett@u.washington.edu [Istituto Universitario di Studi Superiori (IUSS), I-27100 Pavia (Italy); and others

    2012-04-01

    We present the second catalog of high-energy {gamma}-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24 month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 MeV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely {gamma}-ray-producing source classes.

  17. Switchable Fermi surface sheets in greigite

    NARCIS (Netherlands)

    Zhang, B.; de Wijs, G. A.; de Groot, R. A.

    2012-01-01

    Greigite (Fe3S4) and magnetite (Fe3O4) are isostructural and isoelectronic ferrimagnets with quite distinct properties. Electronic structure calculations reveal greigite is a normalmetal in contrast to half-metallic magnetite. Greigite shows a complex Fermi surface with a unique influence of relativ

  18. Fermi Large Area Telescope Second Source Catalog

    CERN Document Server

    ,

    2011-01-01

    We present the second catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24-month period. The Second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in 5 energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we att...

  19. Radiatively Induced Fermi Scale in Grand Unification

    DEFF Research Database (Denmark)

    Alanne, Tommi; Meroni, Aurora; Sannino, Francesco;

    2016-01-01

    We consider Grand Unified Theories in which the hierarchy between the unification and the Fermi scale emerges radiatively. Within the Pati-Salam framework, we show that it is possible to construct a viable model where the Higgs is an elementary pseudo-Goldstone boson, and the correct hierarchy...

  20. Automatic Cloud Bursting under FermiCloud

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao [Fermilab; Shangping, Ren [IIT; Garzoglio, Gabriele [Fermilab; Timm, Steven [Fermilab; Bernabeu, Gerard [Fermilab; Kim, Hyun Woo; Chadwick, Keith; Jang, Haengjin [KISTI, Daejeon; Noh, Seo-Young [KISTI, Daejeon

    1900-01-01

    Cloud computing is changing the infrastructure upon which scientific computing depends from supercomputers and distributed computing clusters to a more elastic cloud-based structure. The service-oriented focus and elasticity of clouds can not only facilitate technology needs of emerging business but also shorten response time and reduce operational costs of traditional scientific applications. Fermi National Accelerator Laboratory (Fermilab) is currently in the process of building its own private cloud, FermiCloud, which allows the existing grid infrastructure to use dynamically provisioned resources on FermiCloud to accommodate increased but dynamic computation demand from scientists in the domains of High Energy Physics (HEP) and other research areas. Cloud infrastructure also allows to increase a private cloud’s resource capacity through “bursting” by borrowing or renting resources from other community or commercial clouds when needed. This paper introduces a joint project on building a cloud federation to support HEP applications between Fermi National Accelerator Laboratory and Korea Institution of Science and Technology Information, with technical contributions from the Illinois Institute of Technology. In particular, this paper presents two recent accomplishments of the joint project: (a) cloud bursting automation and (b) load balancer. Automatic cloud bursting allows computer resources to be dynamically reconfigured to meet users’ demands. The load balance algorithm which the cloud bursting depends on decides when and where new resources need to be allocated. Our preliminary prototyping and experiments have shown promising success, yet, they also have opened new challenges to be studied

  1. Automatic Cloud Bursting under FermiCloud

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao [Fermilab; Shangping, Ren [IIT; Garzoglio, Gabriele [Fermilab; Timm, Steven [Fermilab; Bernabeu, Gerard [Fermilab; Kim, Hyun Woo; Chadwick, Keith; Jang, Haengjin [KISTI, Daejeon; Noh, Seo-Young [KISTI, Daejeon

    2013-01-01

    Cloud computing is changing the infrastructure upon which scientific computing depends from supercomputers and distributed computing clusters to a more elastic cloud-based structure. The service-oriented focus and elasticity of clouds can not only facilitate technology needs of emerging business but also shorten response time and reduce operational costs of traditional scientific applications. Fermi National Accelerator Laboratory (Fermilab) is currently in the process of building its own private cloud, FermiCloud, which allows the existing grid infrastructure to use dynamically provisioned resources on FermiCloud to accommodate increased but dynamic computation demand from scientists in the domains of High Energy Physics (HEP) and other research areas. Cloud infrastructure also allows to increase a private cloud’s resource capacity through “bursting” by borrowing or renting resources from other community or commercial clouds when needed. This paper introduces a joint project on building a cloud federation to support HEP applications between Fermi National Accelerator Laboratory and Korea Institution of Science and Technology Information, with technical contributions from the Illinois Institute of Technology. In particular, this paper presents two recent accomplishments of the joint project: (a) cloud bursting automation and (b) load balancer. Automatic cloud bursting allows computer resources to be dynamically reconfigured to meet users’ demands. The load balance algorithm which the cloud bursting depends on decides when and where new resources need to be allocated. Our preliminary prototyping and experiments have shown promising success, yet, they also have opened new challenges to be studied

  2. Fermi Large Area Telescope Second Source Catalog

    Science.gov (United States)

    Nolan, P. L.; Abdo, A. A.; Ackermann, M.; Ajello, M; Allafort, A.; Antolini, E; Bonnell, J.; Cannon, A.; Celik O.; Corbet, R.; Davis, D. S.; DeCesar, M. E.; Ferrara, E. C.; Gehrels, N.; Harding, A. K.; Hays, E.; Johnson, T. E.; McConville, W.; McEnery, J. E; Perkins, J. S.; Racusin, J. L; Scargle, J. D.; Stephens, T. E.; Thompson, D. J.; Troja, E.

    2012-01-01

    We present the second catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24-month period. The Second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in 5 energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 11eV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely gamma-ray-producing source classes.

  3. Primary experimental studies on mid-infrared FEL irradiation on dental substances at BFEL

    CERN Document Server

    Biao, Z J; Gao Xue Ju; He Wei; Huang Yu Ying; Li Yong Gui; LiuNianQing; Wang Min Kai; Wu Gan; Yan Xue Pin; Zhang Guo Qing

    2001-01-01

    A free electron laser (FEL) with its characteristics of wide wavelength tunability, ultrashort pulse time structure, and high peak power density is predominantly superior to all other conventional lasers in applications. Several experimental studies on mid-infrared FEL irradiation on dental enamel and dentine were performed at the Beijing FEL. Experimental aims were to investigate changes in the hardness, ratios of P to Ca and Cs before and after irradiation on samples with a characteristic absorption wavelength of 9.66 mu m, in the colors of these sample surfaces after irradiation with different wavelengths around the peak wavelength. The time dependence of temperature of the dentine sample was measured with its ps pulse effects compared to that with a continuous CO sub 2 laser. FTIR absorption spectra in the range of 2.5-15.4 mu m for samples of these hard dental substances and pure hydroxyapatite were first examined to decide their chemical components and absorption maximums. Primary experimental results w...

  4. The general solution of the eigenvalue problem for a high-gain FEL

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2001-01-01

    The exact solution of the eigenvalue equation for a high-gain FEL derived in Xie (Nucl. Instr. and Meth. A 445 (2000) 59) is generalized in order to include the space charge effects. This solution is valid not only for natural undulator focusing, but also for alternating-gradient focusing under some condition that is presented. At such, the obtained solution includes all the important effects in the system of axially homogeneous electron beam and undulator: diffraction, betatron motion, energy spread, space charge and frequency detuning. It is valid for ground TEM sub 0 sub 0 mode as well as for high-order modes and can be used for calculation of high-gain FEL amplifiers operating in the wavelength regions from far infrared down to X-ray. In addition, a computationally efficient approximate solution for TEM sub 0 sub 0 mode is derived providing high accuracy (better than 1% in the whole range of parameters). It can be used for quick optimization of FEL amplifiers.

  5. Development of photoinjector RF cavity for high-power CW FEL

    Science.gov (United States)

    Kurennoy, S. S.; Schrage, D. L.; Wood, R. L.; Young, L. M.; Schultheiss, T.; Christina, V.; Rathke, J.

    2004-08-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high-power CW FEL. A preliminary design of the first, and the most challenging, section of a 700-MHz CW RF normal-conducting photoinjector—a 2.5-cell, pi-mode cavity with solenoidal magnetic field for emittance compensation—is completed. Beam dynamics simulations demonstrate that this cavity with an electric field gradient of 7 MV/m will produce an electron beam at 2.7 MeV with the transverse rms emittance 7 mm mrad at 3 nC of charge per bunch. Electromagnetic field computations combined with a thermal and stress analysis show that the challenging problem of cavity cooling can be successfully resolved. We are in the process of building a 100-mA (3 nC of bunch charge at 33.3 MHz bunch repetition rate) photoinjector for demonstration purposes. Its performance parameters will enable a robust 100-kW-class FEL operation with electron beam energy below 100 MeV. The design is scalable to higher power levels by increasing the electron bunch repetition rate and provides a path to a MW-class amplifier FEL.

  6. Development of photoinjector RF cavity for high-power CW FEL

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S.S. E-mail: kurennoy@lanl.gov; Schrage, D.L.; Wood, R.L.; Young, L.M.; Schultheiss, T.; Christina, V.; Rathke, J

    2004-08-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high-power CW FEL. A preliminary design of the first, and the most challenging, section of a 700-MHz CW RF normal-conducting photoinjector - a 2.5-cell, pi-mode cavity with solenoidal magnetic field for emittance compensation - is completed. Beam dynamics simulations demonstrate that this cavity with an electric field gradient of 7 MV/m will produce an electron beam at 2.7 MeV with the transverse rms emittance 7 mm mrad at 3 nC of charge per bunch. Electromagnetic field computations combined with a thermal and stress analysis show that the challenging problem of cavity cooling can be successfully resolved. We are in the process of building a 100-mA (3 nC of bunch charge at 33.3 MHz bunch repetition rate) photoinjector for demonstration purposes. Its performance parameters will enable a robust 100-kW-class FEL operation with electron beam energy below 100 MeV. The design is scalable to higher power levels by increasing the electron bunch repetition rate and provides a path to a MW-class amplifier FEL.

  7. Step-tapered operation of the FEL: efficiency enhancement and two-colour operation

    Science.gov (United States)

    Jaroszynski, D. A.; Prazeres, R.; Glotin, F.; Marcouillé, O.; Ortega, J. M.; Oepts, D.; van der Meer, A. F. G.; Knippels, G. M. H.; van Amersfoort, P. W.

    1996-02-01

    We present measurements of the temporal and spectral properties of radiation produced from the step-tapered undulator infrared free-electron lasers (FELs), CLIO in France and FELIX in the Netherlands. Using a two section undulator with independently adjustable deflection parameters, K, the FEL will operate either with an enhanced efficiency and improved spectral properties (with a small positive ΔK step) or simultaneously at two frequencies (for large ΔK). Using a dispersion-free hole output coupler the maximum wavelength difference {δλ}/{λ}, has now been extended to more than {δλ}/{λ} ≈ 0.6. We also present measurements that show that the FEL FELIX will produce significant power simultaneously at two wavelengths by coherent spontaneous emission when the wavelength is long and the electron bunch is short. The efficiency, spectral and temporal properties have been measured. We show that at the maximum efficiency, ΔK ≈ 0.02, the optical pulses generated are smooth and close to Fourier transform limited. By adjusting ΔK the optical pulse duration can be varied by a factor of 2 or more and sidebands due to synchrotron oscillations can be suppressed.

  8. Harmonic Generation at Lower Electron Energies for a Hard X-ray FEL

    Energy Technology Data Exchange (ETDEWEB)

    Marksteiner, Quinn R. [Los Alamos National Laboratory

    2011-01-01

    There are several schemes currently being investigated to pre-bunch the electron beam and step the coherent bunching up to higher harmonics, all which require modulator sections which introduce additional energy modulation. X-ray FELs operate in a regime where the FEL parameter, {rho} is equal to or less than the effective energy spread introduced from the emittance in the electron beam. Because of this large effective energy spread, the energy modulation introduced from harmonic generation schemes would seriously degrade FEL performance. This problem can be mitigated by incorporating the harmonic generation scheme at a lower electron kinetic energy than the energy at the final undulator. This will help because the effective energy spread from emittance is reduced at lower energies, and can be further reduced by making the beam transversely large. Then the beam can be squeezed down slowly enough in the subsequent accelerator sections so that geometric debunching is mitigated. The beam size inside the dispersive chicanes and in the accelerator sections must be carefully optimized to avoid debunching, and each subharmonic modulator section must generate enough energy modulation to overcome the SASE noise without significantly increasing the gain length in the final undulator. Here we show analytical results that demonstrate the feasibility of this harmonic pre-bunching scheme.

  9. High-gain Seeded FEL Amplifier Tunable in the Terahertz Range

    CERN Document Server

    Sung, C; Pellegrini, C; Ralph, J E; Reiche, S; Rosenzweig, J B; Tochitsky, Sergei Ya

    2005-01-01

    The lack of a high-power, relatively low-cost and compact terahertz (THz) source in the range 0.3-3x10(12) Hz is the major obstacle in progressing on biomedical and material studies at these wavelengths. A high-gain, single pass seeded FEL technique allows to obtain high power THz pulses of a high spectral brightness. We describe an ongoing project at the Neptune laboratory where a ~ 1kW seed pulse generated by difference frequency mixing of CO2 laser lines in a GaAs nonlinear crystal is injected into a waveguide FEL amplifier. The FEL is driven by a 5 ps (r.m.s) long electron pulse with a peak current up to 100A provided by a regular S-band photoinjector. According to 3-D, time dependent simulations, up to ~ 10 MW THz power can be generated using a 2 meter long planar undulator. By mixing different pairs of CO2 laser lines and matching resonant energy of the electron beam, tunability in the 100-400 mm range is expected. A tunable Fabri-Perot interferometer will be used to select a high-power 5ps THz pulse. T...

  10. Investigation of bunch repetition rate deviations in FIR FEL driven by a magnetron-based microtron

    CERN Document Server

    Kazakevitch, Grigori M; Lee Byung Cheol; Lee, J

    2002-01-01

    The stability of the bunch repetition rate in a FIR FEL driven by a 2.8 GHz magnetron-based microtron was investigated using a heterodyne method with a low Q-factor straight-flight measuring cavity. The measuring cavity is located in the straight section of the FIR FEL injection beam line and is excited by the passage of electron bunches. The RF signal from the measuring cavity coupling loop was mixed with a precise heterodyne signal with a frequency difference of several MHz. The beat frequency was analyzed to obtain the temporal distribution of the bunch repetition rate deviation during the macro pulse of the electron beam. The time resolution and the accuracy of measurements are approximately 100 ns and a few kHz, respectively. Based on this data, we could determine the level and shape of the magnetron current and the initial frequency shift between magnetron and accelerating cavity for the FEL operation in the wavelength range 100-300 microns.

  11. High-precision half-life and branching-ratio measurements for superallowed Fermi β+ emitters at TRIUMF – ISAC

    Directory of Open Access Journals (Sweden)

    Laffoley A. T.

    2014-03-01

    Full Text Available A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF’s Isotope Separator and Accelerator (ISAC radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB corrections in superallowed Fermi β decays.

  12. [Effect on Fermi Resonance by Some External Fields: Investigation of Fermi Resonance According to Raman Spectra].

    Science.gov (United States)

    Jiang, Xiu-lan; Sun, Cheng-lin; Zhou, Mi; Li, Dong-fei; Men, Zhi-wei; Li, Zuo-wei; Gao, Shu-qin

    2015-03-01

    Fermi resonance is a phenomenon of molecular vibrational coupling and energy transfer occurred between different groups of a single molecule or neighboring molecules. Many properties of Fermi resonance under different external fields, the investigation method of Raman spectroscopy as well as the application of Fermi resonance, etc need to be developed and extended further. In this article the research results and development about Fermi resonance obtained by Raman spectral technique were introduced systematically according to our work and the results by other researchers. Especially, the results of the behaviors of intramolecular and intermolecular Fermi resonance of some molecules under some external fields such as molecular field, pressure field and temperature field, etc were investigated and demonstrated in detail according to the Raman spectra obtained by high pressure DAC technique, temperature variation technique as well as the methods we planed originally in our group such as solution concentration variation method and LCOF resonance Raman spectroscopic technique, and some novel properties of Fermi resonance were found firstly. Concretely, (1) Under molecular field. a. The Raman spectra of C5H5 N in CH3 OH and H2O indicates that solvent effect can influence Fermi resonance distinctly; b. The phenomena of the asymmetric movement of the Fermi resonance doublets as well as the fundamental involved is tuned by the Fermi resonance which had not been found by other methods were found firstly by our variation solution concentration method; c. The Fermi resonance properties can be influenced distinctly by the molecular group reorganization induced by the hydrogen bond and anti-hydrogen bond in solution; d. Fermi resonance can occurred between C7 H8 and m-C8H10, and the Fermi resonance properties behave quite differently with the solution concentration; (2) Under pressure field. a. The spectral lines shift towards high wavenumber with increasing pressure, and

  13. The basis of the Fermi liquid theory

    CERN Document Server

    Apostol, M

    2001-01-01

    Interaction may affect drastically the many-particle ensembles; for instance an attraction, even weak, between electrons, binds them up in pairs, leading to superconductivity; interacting fermions in one dimension get bosonized; anisotropic fermions with 'nested' Fermi surfaces become non-homogeneous, when interacting, and develop charge- or spin- density waves. All these are different phases, and appear as symmetry breakings, spontaneous or induced; they are also termed as instabilities of the many-body systems, under interaction. Hints toward their nature are often obtained through studying the interacting two-particle problem, scattering included. In this paper the basis of the Fermi liquid theory is shown, and electronic liquid is briefly discussed. (author)

  14. Quantum gravity as a Fermi liquid

    CERN Document Server

    Alexander, Stephon H S

    2008-01-01

    We present a reformulation of loop quantum gravity with a cosmological constant and no matter as a Fermi-liquid theory. When the topological sector is deformed and large gauge symmetry is broken, we show that the Chern-Simons state reduces to Jacobson's degenerate sector describing 1+1 dimensional propagating fermions with nonlocal interactions. The Hamiltonian admits a dual description which we realize in the simple BCS model of superconductivity. On one hand, Cooper pairs are interpreted as wormhole correlations at the de Sitter horizon; their number yields the de Sitter entropy. On the other hand, BCS is mapped into a deformed conformal field theory reproducing the structure of quantum spin networks. When area measurements are performed, Cooper-pair insertions are activated on those edges of the spin network intersecting the given area, thus providing a description of quantum measurements in terms of excitations of a Fermi sea to superconducting levels. The cosmological constant problem is naturally addres...

  15. Relativistic Beaming Effect in Fermi Blazars

    Indian Academy of Sciences (India)

    J. H. Fan; D. Bastieri; J. H. Yang; Y. Liu; D. X. Wu; S. H. Li

    2014-09-01

    The most identified sources observed by Fermi/LAT are blazars, based on which we can investigate the emission mechanisms and beaming effect in the -ray bands for blazars. Here, we used the compiled around 450 Fermi blazars with the available X-ray observations to estimate their Doppler factors and compared them with the integral -ray luminosity in the range of 1–100 GeV. It is interesting that the integral -ray luminosity is closely correlated with the estimated Doppler factor, log = (2.95 ± 0.09) log + 43.59 ± 0.08 for the whole sample. When the dependence of the correlation between them and the X-ray luminosity is removed, the correlation is still strong, which suggests that the -ray emissions are strongly beamed.

  16. Magnetar Observations in the Fermi Era

    Science.gov (United States)

    Kouveliotou, Chryssa

    2009-01-01

    NASA s Fermi Observatory was launched June 11, 2009; the Fermi Gamma Ray Burst Monitor (GBM) began normal operations on July 14, about a month after launch, when the trigger algorithms were enabled. In the first 8 months of operations we recorded emission of three magnetar sources; of these, only one was an old magnetar: SGR 1806+20. The other two detections were: SGR J0501+4516, newly discovered with Swift and extensively monitored with both Swift and GBM, and SGR J1550-5418, a source originally classified as an Anomalous X-ray Pulsar (AXP). I report below on the current status of the analyses efforts of all these GBM data sets, combined with data from other satellites (Spitzer, RXTE, Chandra, Swift).

  17. Magnetar Observations with Fermi/GBM

    Science.gov (United States)

    Kouveliotou, Chryssa

    2009-01-01

    NASA's Fermi Observatory was launched June 11, 2009; the Fermi Gamma Ray Burst Monitor (GBM) began normal operations on July 14, about a month after launch, when the trigger algorithms were enabled. In the first year of operations we recorded emission from four magnetar sources; of these, only one was an old magnetar: SGR 1806+20. The other three detections were: SGR J0501+4516, newly discovered with Swift and extensively monitored with both Swift and GBM, SGR J1550-5418, a source originally classified as an Anomalous X-ray Pulsar (AXP) and a very recently discovered new source, SGR 0418+5729. I report below on the current status of the analyses efforts of the GBM data.

  18. A Probabilistic Analysis of the Fermi Paradox

    CERN Document Server

    Solomonides, Evan; Terzian, Yervant

    2016-01-01

    The fermi paradox uses an appeal to the mediocrity principle to make it seem counter-intuitive that humanity has not been contacted by extraterrestrial intelligence. A numerical, statistical analysis was conducted to determine whether this apparent loneliness is, in fact, unexpected. An inequality was derived to relate the frequency of life arising and developing technology on a suitable planet in the galaxy, the average length of time since the first broadcast of such a civilization, and a constant term. An analysis of the sphere reached thus far by human communication was also conducted, considering our local neighborhood and planets of particular interest. We clearly show that human communication has not reached a number of stars and planets adequate to expect an answer. These analyses both conclude that the Fermi paradox is not, in fact, unexpected. By the mediocrity principle and numerical modeling, it is actually unlikely that the Earth would have been reached by extraterrestrial communication at this p...

  19. Unconventional Fermi surface in an insulating state

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tan, B. S. [Cambridge Univ., Cambridge (United Kingdom); Hsu, Y. -T. [Cambridge Univ., Cambridge (United Kingdom); Zeng, B. [National High Magnetic Field Lab., Tallahassee, FL (United States); Hatnean, M. Ciomaga [Univ. of Warwick, Coventry (United Kingdom); Zhu, Z. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hartstein, M. [Cambridge Univ., Cambridge (United Kingdom); Kiourlappou, M. [Cambridge Univ., Cambridge (United Kingdom); Srivastava, A. [Cambridge Univ., Cambridge (United Kingdom); Johannes, M. D. [Center for Computational Materials Science, Washington, DC (United States); Murphy, T. P. [National High Magnetic Field Lab., Tallahassee, FL (United States); Park, J. -H. [National High Magnetic Field Lab., Tallahassee, FL (United States); Balicas, L. [National High Magnetic Field Lab., Tallahassee, FL (United States); Lonzarich, G. G. [Cambridge Univ., Cambridge (United Kingdom); Balakrishnan, G. [Univ. of Warwick, Coventry (United Kingdom); Sebastian, Suchitra E. [Cambridge Univ., Cambridge (United Kingdom)

    2015-07-17

    Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. As a result, the quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

  20. Improved Performance of the NIJI-IV Compact VUV/IR FEL and its Application to the Surface Observation

    CERN Document Server

    Yamada, Kawakatsu; Sei, Norihiro; Yagi-Watanabe, K; Yasumoto, Masato

    2004-01-01

    At AIST, efforts to increase the FEL power as well as to shorten the lasing wavelength below 190 nm are being made, to use the NIJI-IV FEL as an intense light source for real-time surface observation using the photoelectron emission microscopy (PEEM). By irradiating a transition-metal surface with the 200-nm FEL, fine structure of one- micron scale was successfully observed with spatial and temporal resolutions of a few hundreds nm and 33 ms, respectively. In addition, a 3.6-m optical klystron for lasing in the infrared was recently installed into the north straight section of the NIJI-IV to extend the lasing wavelength range up to ~ 10 microns. One of our interests in the infrared-FEL application is to utilize it for a Raman spectroscopy which can examine adsorbed molecules and their bonding conditions on the metal surface. Establishment of a total surface analysis system using NIJI-IV compact VUV/IR FEL combined with characteristic surface analysis techniques is one of our goals in the near future. Improved...

  1. Pulsar Timing with the Fermi LAT

    CERN Document Server

    Ray, Paul S; Parent, Damien; PSC, the Fermi

    2010-01-01

    We present an overview of precise pulsar timing using data from the Large Area Telescope (LAT) on Fermi. We describe the analysis techniques including a maximum likelihood method for determining pulse times of arrival from unbinned photon data. In addition to determining the spindown behavior of the pulsars and detecting glitches and timing noise, such timing analyses allow the precise determination of the pulsar position, thus enabling detailed multiwavelength follow up.

  2. EIS: the scattering beamline at FERMI.

    Science.gov (United States)

    Masciovecchio, Claudio; Battistoni, Andrea; Giangrisostomi, Erika; Bencivenga, Filippo; Principi, Emiliano; Mincigrucci, Riccardo; Cucini, Riccardo; Gessini, Alessandro; D'Amico, Francesco; Borghes, Roberto; Prica, Milan; Chenda, Valentina; Scarcia, Martin; Gaio, Giulio; Kurdi, Gabor; Demidovich, Alexander; Danailov, Miltcho B; Di Cicco, Andrea; Filipponi, Adriano; Gunnella, Roberto; Hatada, Keisuke; Mahne, Nicola; Raimondi, Lorenzo; Svetina, Cristian; Godnig, Roberto; Abrami, Alessandro; Zangrando, Marco

    2015-05-01

    The Elastic and Inelastic Scattering (EIS) beamline at the free-electron laser FERMI is presented. It consists of two separate end-stations: EIS-TIMEX, dedicated to ultrafast time-resolved studies of matter under extreme and metastable conditions, and EIS-TIMER, dedicated to time-resolved spectroscopy of mesoscopic dynamics in condensed matter. The scientific objectives are discussed and the instrument layout illustrated, together with the results from first exemplifying experiments.

  3. Higher time derivatives, stability and Fermi Statistics

    CERN Document Server

    Lopez-Sarrion, Justo

    2011-01-01

    We show that statistics is crucial for the instability problem derived from higher time derivatives. In fact, and contrary to previous statements, we check that when dealing with Fermi systems, the Hamiltonian is well bounded and the quantum states are normalizable. Although, ghost states are still present, they do not affect unitarity under certain conditions. We first analyze a quantum oscillator involving Grassman variables and then we generalize it to a Dirac field. Finally, we discuss some physical implications

  4. Fermi Large Area Telescope Second Source Catalog

    Science.gov (United States)

    Nolan, P. L.; Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Belfiore, A.; Bellazzini, R.; Berenji, B.; Bignami, G. F.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Bonnell, J.; Borgland, A. W.; Bottacini, E.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Campana, R.; Cañadas, B.; Cannon, A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Ceccanti, M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chipaux, R.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Corbet, R.; Cutini, S.; D'Ammando, F.; Davis, D. S.; de Angelis, A.; DeCesar, M. E.; DeKlotz, M.; De Luca, A.; den Hartog, P. R.; de Palma, F.; Dermer, C. D.; Digel, S. W.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Dumora, D.; Enoto, T.; Escande, L.; Fabiani, D.; Falletti, L.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Iafrate, G.; Itoh, R.; Jóhannesson, G.; Johnson, R. P.; Johnson, T. E.; Johnson, A. S.; Johnson, T. J.; Kamae, T.; Katagiri, H.; Kataoka, J.; Katsuta, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Lande, J.; Landriu, D.; Latronico, L.; Lemoine-Goumard, M.; Lionetto, A. M.; Llena Garde, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Marelli, M.; Massaro, E.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Minuti, M.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Mongelli, M.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Naumann-Godo, M.; Norris, J. P.; Nuss, E.; Nymark, T.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Perkins, J. S.; Pesce-Rollins, M.; Pierbattista, M.; Pinchera, M.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Rochester, L. S.; Romani, R. W.; Roth, M.; Rousseau, R.; Ryde, F.; Sadrozinski, H. F.-W.; Salvetti, D.; Sanchez, D. A.; Saz Parkinson, P. M.; Sbarra, C.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Shaw, M. S.; Shrader, C.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Stephens, T. E.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Tinebra, F.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vandenbroucke, J.; Van Etten, A.; Van Klaveren, B.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Wallace, E.; Wang, P.; Werner, M.; Winer, B. L.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.; Zimmer, S.

    2012-04-01

    We present the second catalog of high-energy γ-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24 month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 MeV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely γ-ray-producing source classes. We dedicate this paper to the memory of our colleague Patrick Nolan, who died on 2011 November 6. His career spanned much of the history of high-energy astronomy from space and his work on the Large Area Telescope (LAT) began nearly 20 years ago when it was just a concept. Pat was a central member in the operation of the LAT collaboration and he is greatly missed.

  5. Signatures of an annular Fermi sea

    Science.gov (United States)

    Jo, Insun; Liu, Yang; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Shayegan, M.; Winkler, R.

    2017-01-01

    The concept of a Fermi surface, the constant-energy surface containing all the occupied electron states in momentum, or wave-vector (k ) , space plays a key role in determining electronic properties of conductors. In two-dimensional (2D) carrier systems, the Fermi surface becomes a contour which, in the simplest case, encircles the occupied states. In this case, the area enclosed by the contour, which we refer to as the Fermi sea (FS), is a simple disk. Here we report the observation of an FS with a new topology, namely, an FS in the shape of an annulus. Such an FS is expected in a variety of 2D systems where the energy band dispersion supports a ring of extrema at finite k , but its experimental observation has been elusive. Our study provides (1) theoretical evidence for the presence of an annular FS in 2D hole systems confined to wide GaAs quantum wells and (2) experimental signatures of the onset of its occupation as an abrupt rise in the sample resistance, accompanied by a sudden appearance of Shubnikov-de Haas oscillations at an unexpectedly high frequency whose value does not simply correspond to the (negligible) density of holes contained within the annular FS.

  6. A hybrid Fermi-Ulam-bouncer model

    Energy Technology Data Exchange (ETDEWEB)

    Leonel, Edson D; McClintock, P V E [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2005-01-28

    Some dynamical and chaotic properties are studied for a classical particle bouncing between two rigid walls, one of which is fixed and the other moves in time, in the presence of an external field. The system is a hybrid, behaving not as a purely Fermi-Ulam model, nor as a bouncer, but as a combination of the two. We consider two different kinds of motion of the moving wall: (i) periodic and (ii) random. The dynamics of the model is studied via a two-dimensional nonlinear area-preserving map. We confirm that, for periodic oscillations, our model recovers the well-known results of the Fermi-Ulam model in the limit of zero external field. For intense external fields, we establish the range of control parameters values within which invariant spanning curves are observed below the chaotic sea in the low energy domain. We characterize this chaotic low energy region in terms of Lyapunov exponents. We also show that the velocity of the particle, and hence also its kinetic energy, grow according to a power law when the wall moves randomly, yielding clear evidence of Fermi acceleration.

  7. Women in Physics in Fermi's Time

    CERN Document Server

    Byers, N

    2003-01-01

    Enrico Fermi lived from 1901 to 1955, a period of great progress in physics and a period in which opportunities for women to study and work in institutions of higher learning increased significantly in Europe and North America. Though there are a few examples of women who made important contributions to physics in the 18th century such as Emilie du Chatelet and Laura Bassi, it was only in Fermi's time that the number began to increase significantly. It is remarkable that almost immediately after they gained entrance to laboratories and universities, among them appeared women of great creative ability who made lasting contributions to physics. This talk is mainly about some of these whose scientific lives are not as well known as their contributions deserve - Emmy Noether, Marietta Blau, Irene Joliot-Curie, Lise Meitner. Additionally, some outstanding women whose work played a role in Enrico Fermi's life in physics are noted - Ida Tacke Noddack, Tatiana Ehrenfest-Afanaseva, Leona Woods Marshall Libby, and Mari...

  8. A Probabilistic Analysis of the Fermi Paradox

    Science.gov (United States)

    Solomonides, Evan; Terzian, Yervant

    2016-06-01

    The Fermi paradox uses an appeal to the mediocrity principle to make it seem counterintuitive that humanity has not been contacted by extraterrestrial intelligence. A numerical, statistical analysis was conducted to determine whether this apparent loneliness is, in fact, unexpected. An inequality was derived to relate the frequency of life arising and developing technology on a suitable planet in the galaxy; the average length of time since the first broadcast of such a civilization; and a constant term. An analysis of the sphere reached thus far by human communication was also conducted, considering our local neighborhood and planets of particular interest. These analyses both conclude that the Fermi paradox is not, in fact, unexpected. By the mediocrity principle and numerical modeling, it is actually unlikely that the Earth would have been reached by extraterrestrial communication at this point. We predict that under 1% of the galaxy has been reached at all thus far, and we do not anticipate to be reached until approximately 50% of stars/planets have been reached. We offer a prediction that we should not expect this until at least 1,500 years in the future. Thus the Fermi paradox is not a shocking observation- or lack thereof- and humanity may very well be contacted within our species’ lifespan (we can begin to expect to be contacted 1,500 years in the future).

  9. Superconducting instability in non-Fermi liquids

    CERN Document Server

    Mandal, Ipsita

    2016-01-01

    We use renormalization group (RG) analysis and dimensional regularization techniques to study potential superconductivity-inducing four-fermion interactions in systems with critical Fermi surfaces of general dimensions ($m$) and co-dimensions ($d-m$), arising as a result of quasiparticle interaction with a gapless Ising-nematic order parameter. These are examples of non-Fermi liquid states in $d$ spatial dimensions. Our formalism allows us to treat the corresponding zero-temperature low-energy effective theory in a controlled approximation close to the upper critical dimension $d=d_c(m)$. The fixed points are identified from the RG flow equations, as functions of $d$ and $m$. We find that the flow towards the non-Fermi liquid fixed point is preempted by Cooper pair formation for both the physical cases of $(d=3, m=2)$ and $(d=2, m=1)$. In fact, there is a strong enhancement of superconductivity by the order parameter fluctuations at the quantum critical point.

  10. Facilities & Leadership

    Data.gov (United States)

    Department of Veterans Affairs — The facilities web service provides VA facility information. The VA facilities locator is a feature that is available across the enterprise, on any webpage, for the...

  11. Investigations on the electron bunch distribution in the longitudinal phase space at a laser driven RF electron source for the European X-FEL

    Energy Technology Data Exchange (ETDEWEB)

    Roensch, Juliane

    2010-01-15

    The Photoinjector Test facility at DESY, Zeuthen site, (PITZ) is aiming for the optimization of electron guns for SAS-FELs. For this it is necessary to investigate the characteristics of the six dimensional phase space of the bunch produced by a photoinjector. This thesis is focused on the analysis of the longitudinal properties of the electron bunch distribution, this means the temporal current distribution and the momentum distribution as well as the correlation of both properties. The complete distribution of the electron bunch in longitudinal phase space of a photoinjector was measured directly for the first time at a beam momentum of about 5 MeV/c, using an existing apparatus. This system had been designed for an accelerating gradient of 40 MV/m. Its subcomponents were analysed to understand sources of uncertainties of the measurement system. The usage of higher accelerating gradients in the gun (60 MV/m, resulting in a beam momentum of about 6.8 MeV/c) demands major modifications of the existing measurement system for the longitudinal phase space distribution. An upgrade of the facility by an additional accelerating cavity required the design of further longitudinal diagnostics systems for the analysis at higher momenta (up to 40 MeV/c). Measurements of the longitudinal beam properties to determine the influence of different operation parameters, like RF launch phase, charge, accelerating field gradient and laser distribution were performed and compared to simulations. (orig.)

  12. Core-dominance parameter, black hole mass and jet-disc connection in Fermi blazars

    OpenAIRE

    Chen, Y. Y.; Zhang, X.; Zhang, H. J.; X. L. Yu

    2015-01-01

    We study the relationship between jet power and accretion for Fermi and non-Fermi blazars, respectively. We also compare the relevant parameter between them. Our main results are as follows. (i) Fermi and non-Fermi blazars have significant difference in redshift, black hole mass, and broad line luminosity. (ii) Fermi blazars have higher average core-dominance parameter than non-Fermi blazars, which suggests that Fermi blazars have strong beaming effect. (iii) We find significant correlation b...

  13. Biochemistry Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Biochemistry Facility provides expert services and consultation in biochemical enzyme assays and protein purification. The facility currently features 1) Liquid...

  14. Parameter Analysis For A High-Gain Harmonic Generation FEL By Numerical Calculation Based On 1D Theory

    CERN Document Server

    Li, Yuhui; Zhang, Shancai

    2004-01-01

    The high-gain harmonic generation (HGHG) free-electron laser (FEL) is an important candidate for a fourth-generation light source. Lots of theoretical work has been performed. Recently a further 1D theory about HGHG FEL has been developed. It considers the effects of different parameters for the whole process. An initial program based on this theory has been made. In this paper, a brief comparison of the results from this 1D program and from TDA (3D code) is discussed. It also analyses the parameters for Shanghai deep ultra violate free-electron laser source (SDUV-FEL), including electron beam energy spread, seed laser power, strength of dispersion section etc.

  15. Photoelectron sidebands induced by a chirped laser field for shot-by-shot temporal characterization of FEL pulses

    Science.gov (United States)

    Liu, Chien-Nan; Morishita, Toru; Fushitani, Mizuho; Hishikawa, Akiyoshi

    2016-02-01

    We theoretically investigate the laser-assisted photoionization of He by an extreme ultra violet (XUV) pulse in the presence of a linearly chirped intense laser pulse by solving the time-dependent Schrödinger equation within the single-active-electron approximation. Analysis based on the time-dependent perturbation theory is also carried out to provide more physical insights. A new scheme is shown to be capable of extracting the arrival time of an XUV free-electron laser (FEL) pulse relative to an external laser pulse as well as the XUV pulse duration from the photoelectron sidebands resulting from XUV ionization in the presence of a chirped laser pulse. This scheme is independent of the energy fluctuation and the timing jittering of the FEL pulse. Therefore it can be implemented in a non-invasive way to characterize FEL pulses on a shot-by-shot basis in time-resolved spectroscopy.

  16. Wavefront propagation through the beamline designed for seeding the DESY XUV FEL

    CERN Document Server

    Reininger, R; Gürtler, P; Bahrdt, J

    2001-01-01

    A beamline designed to reduce the spectral bandwidth of the DESY XUV FEL is described. The beamline is intended to cover the wavelength range from 6.4 to 50 nm with three variable line spacing gratings. A plane mirror in front of the grating is used to maintain constant magnification in the dispersion direction. The electric field generated by the first undulator at three wavelengths, 6.4, 13, and 25 nm, is propagated through the beamline. The results show that the beamline has the resolution and imaging properties required for seeding the second undulator at these wavelengths.

  17. A 4 to 0.1 nm FEL Based on the SLAC Linac

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C.; /UCLA

    2012-06-05

    The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region and subpicosecond pulse length.

  18. Resonantly Enhanced Multiphoton Ionization under XUV FEL radiation: A case study of the role of harmonics

    CERN Document Server

    Nikolopoulos, Georgios M

    2016-01-01

    We provide a detailed quantitative study of the possible role of a small admixture of harmonics on resonant two-photon ionization. The motivation comes from the occasional presence of 2nd and 3rd harmonics in FEL radiation. We obtain the dependence of ionic yields on the intensity of the fundamental, the percentage of 2nd harmonic and the detuning of the fundamental from resonance. Having examined the cases of one and two intermediate resonances, we arrive at results of general validity and global behavior, showing that even a small amount of harmonic may seem deceptively innocuous.

  19. An Rf-gun-driven recirculated linac as injector and FEL driver.

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, A.; Biedron, S.; Eriksson, M.; Freund, H.; Werin, S.

    1999-08-23

    A new pre-injector for the MAX-Laboratory is under design and construction. A thermionic rf gun, designed to operate at medium currents with low back bombardment power, is under construction. The gun will, via a magnetic compressor and energy filter, feed a recirculated linac consisting of two SLED-equipped structures giving 125 MeV each. The first will be delivered in 1999. The system is aimed as a pre-injector for the existing storage rings at MAX-Lab, but will also open up possibilities for a SASE FEL in the UV reaching above 100 MW below 100 run.

  20. Design of energy-recovery transport for the JAERI FEL driven by a superconducting linac

    CERN Document Server

    Hajima, R; Nagai, R; Kikuzawa, N; Nishimori, N; Shizuma, T; Minehara, E J; Vinokurov, N A

    2000-01-01

    A high-average power free-electron laser driven by a superconducting linac has been developed in Japan Atomic Energy Research Institute (JAERI), and stable laser output over 0.1 kW in infrared region is now available. For further increasing of FEL output power, installing energy-recovery transport has been planned. The lattice design for the energy-recovery transport is discussed in the present paper. It is found that a recirculation transport, which fulfills the requirements for energy acceptance and isochronicity, can be realized by adding another triple-bend arc to the existing beam line.

  1. Measurement and modeling of mirror distortion in a high power FEL

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.; Neil, G.; Michelle D. Shinn

    2000-01-01

    Mirror heating in a high power FEL can alter the optical mode and affect the gain of the laser. This can lead to a large reduction of the laser power from ideal values. Measurements of the power and mode size in the Jefferson Lab IR Demo laser have shown clear evidence of mirror distortion at high average power leading (up to 17 kW incident on the mirrors and over 40 W absorbed per mirror). The measurements and comparisons with modeling will be presented. Both steady state and transient analyses and measurements are considered.

  2. Design of broadly tuned FIR FEL based on a variable-period microwiggler

    Energy Technology Data Exchange (ETDEWEB)

    Qing-Xiang Liu [Institute of Applied Electronics, Sichuan (China)]|[Southwest Jiaotong Univ., Sichuan (China); Yong Xu [Southwest Jiatong Univ., Sichuan (China)

    1995-12-31

    A varible-period microwiggler is proposed and investigated. The fundamental period of the microwiggler is designed as {lambda}o=2mm, and the period of the microwiggler can be turned from {lambda}o to n{lambda}o (n=1,2,3,{hor_ellipsis}) The wiggler fields with the period 3{lambda}o, 4{lambda}o, and 5{lambda}o are measured and compared with the theoretical results. Finally, a broadly tuned FIR FEL is designed based on the performance of the variable-period microwiggler.

  3. New autocorrelation technique for the IR FEL optical pulse width measurements

    Energy Technology Data Exchange (ETDEWEB)

    Amirmadhi, F.; Brau, K.A.; Becker, C. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1995-12-31

    We have developed a new technique for the autocorrelation measurement of optical pulse width at the Vanderbilt University FEL center. This method is based on nonlinear absorption and transmission characteristics of semiconductors such as Ge, Te and InAs suitable for the wavelength range from 2 to over 6 microns. This approach, aside being simple and low cost, removes the phase matching condition that is generally required for the standard frequency doubling technique and covers a greater wavelength range per nonlinear material. In this paper we will describe the apparatus, explain the principal mechanism involved and compare data which have been acquired with both frequency doubling and two-photon absorption.

  4. A new undulator for the extension of the spectral range of the CLIO FEL

    Energy Technology Data Exchange (ETDEWEB)

    Marcouille, O.; Berset, J.M.; Glotin, F. [LURE, Orsay (France)] [and others

    1995-12-31

    We built a new undulator in order to extend the lasing range of the CLIO infrared FEL. Presently, CLIO operates in the wavelength range 2 - 17 {mu}m. Beyond 14 {mu}m, the power decreases rapidly, because of the diffraction losses of the vacuum chamber (7 mm height and 2 m long). Thus, lasing at higher wavelengths implies installing a chamber with a height approximately twice. Then the minimum gap is increased and the maximum deflection parameter, K, is reduced from 2 to 1 : the laser tunability is greatly reduced. This is why a new undulator has been built.

  5. The 18-kDa form of cat allergen Felis domesticus 1 (Fel d 1) is associated with gelatin- and fibronectin-degrading activity

    DEFF Research Database (Denmark)

    Ring, P C; Wan, H; Schou, C;

    2000-01-01

    , allergens that degrade proteins have been suggested to facilitate allergen presentation by increasing parallelular permeability of airways epithelium. However, little information exists to indicate whether Fel d 1 has other activities relevant to allergic responses. OBJECTIVE: To study whether Fel d 1......, suggest that their inhibitory action may be due to noncatalytic site interactions. Alternatively, highly purified Fel d 1 may be associated with an active contaminant, although none were found. CONCLUSION: These results suggest that Fel d 1 is another example of a domestic allergen which is associated...... with enzyme activity. It remains to be established whether the activity resides in Fel d 1 itself or in an unresolved, and possibly related, protein....

  6. Quasiparticle lifetime in a mixture of Bose and Fermi superfluids.

    Science.gov (United States)

    Zheng, Wei; Zhai, Hui

    2014-12-31

    In this Letter, we study the effect of quasiparticle interactions in a Bose-Fermi superfluid mixture. We consider the lifetime of a quasiparticle of the Bose superfluid due to its interaction with quasiparticles in the Fermi superfluid. We find that this damping rate, i.e., the inverse of the lifetime, has quite a different threshold behavior at the BCS and the BEC side of the Fermi superfluid. The damping rate is a constant near the threshold momentum in the BCS side, while it increases rapidly in the BEC side. This is because, in the BCS side, the decay process is restricted by the constraint that the fermion quasiparticle is located near the Fermi surface, while such a restriction does not exist in the BEC side where the damping process is dominated by bosonic quasiparticles of the Fermi superfluid. Our results are related to the collective mode experiment in the recently realized Bose-Fermi superfluid mixture.

  7. Thomas-Fermi-von Weizsaecker theory of atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Benguria, R.; Brezis, H.; Lieb, E.H.

    1981-11-02

    We place the Thomas-Fermi-von Weizsaecker model of atoms on a firm mathematical footing. We prove existence and uniqueness of solutions of the Thomas-Fermi-von Weizsaecker equation as well as the fact that they minimize the Thomas-Fermi-von Weizsaecker energy functional. Moreover, we prove the existence of bindings for two very dissimilar atoms in the frame of this model.

  8. Dipolar Excitations of a Trapped Bose-Fermi Mixture

    Institute of Scientific and Technical Information of China (English)

    FUXiao-Wei; LIUXia-Ji; HUHui; LIShi-Qun

    2004-01-01

    We study the dipolar excitation of a trapped Bose-Fermi mixture at zero temperature, by using a scalingansatz formalism and Thomas-Fermi approximation at mean-field level. We show that both frequencies of the low-lying and high-lying modes are strongly affected by the Bose-Fermi interaction. Possible implication of our results to the recent experiment has been commented.

  9. Dipolar Excitations of a Trapped Bose-Fermi Mixture

    Institute of Scientific and Technical Information of China (English)

    FU Xiao-Wei; LIU Xia-Ji; HU Hui; LI Shi-Qun

    2004-01-01

    We study the dipolar excitation of a trapped Bose-Fermi mixture at zero temperature, by using a scaling ansatz formalism and Thomas-Fermi approximation at mean-field level. We show that both frequencies of the low-lying and high-lying modes are strongly affected by the Bose-Fermi interaction. Possible implication of our results to the recent experiment has been commented.

  10. Induced interactions in a superfluid Bose-Fermi mixture

    DEFF Research Database (Denmark)

    Kinnunen, Jami; Bruun, Georg

    2015-01-01

    -particle and collective excitations of the Fermi gas give rise to an induced interaction between the bosons, which varies strongly with momentum and frequency. It diverges at the sound mode of the Fermi superfluid, resulting in a sharp avoided crossing feature and a corresponding sign change of the interaction energy...... shift in the excitation spectrum of the BEC. In addition, the excitation of quasiparticles in the Fermi superfluid leads to damping of the excitations in the BEC. Besides studying induced interactions themselves, we can use these prominent effects to systematically probe the strongly interacting Fermi...

  11. Theory of the Fermi-level energy in semiconductor superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Luscombe, J.H. (Central Research Laboratories, Texas Instruments Incorporated, Dallas, Texas (USA)); Aggarwal, R. (Central Research Laboratories, Texas Instruments Incorporated, Dallas, Texas (USA) Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (USA)); Reed, M.A. (Central Research Laboratories, Texas Instruments Incorporated, Dallas, Texas (USA) Department of Electrical Engineering, Yale University, New Haven, Connecticut (USA)); Frensley, W.R. (Central Research Laboratories, Texas Instruments Incorporated, Dallas, Texas (USA) Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas (USA)); Luban, M. (Iowa Univ., Iowa City, IA (USA). Dept. of Physics and Astronomy Ames Lab., IA (USA))

    1991-09-15

    A theoretical study of the properties of the Fermi level in semiconductor superlattices (SL's) is made which is based upon the carrier occupation of the minibands in thermal equilibrium. We find, for a fixed carrier density and temperature, that the SL Fermi level can differ significantly from that obtained using commonly employed three-dimensional approximations, depending upon the relative spacings and widths of the minibands, with the SL Fermi level being higher than the corresponding bulk value. We find that the SL Fermi level is a sensitive function of the relative widths of the quantum wells and barriers.

  12. A Nonlocal Poisson-Fermi Model for Ionic Solvent

    CERN Document Server

    Xie, Dexuan; Eisenberg, Bob; Scott, L Ridgway

    2016-01-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-type kernel function. Moreover, the Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Finally, numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  13. Nonlocal Poisson-Fermi model for ionic solvent.

    Science.gov (United States)

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  14. Evolution of electron Fermi surface with doping in cobaltates.

    Science.gov (United States)

    Ma, Xixiao; Lan, Yu; Qin, Ling; Kuang, Lülin; Feng, Shiping

    2016-08-24

    The notion of the electron Fermi surface is one of the characteristic concepts in the field of condensed matter physics, and it plays a crucial role in the understanding of the physical properties of doped Mott insulators. Based on the t-J model, we study the nature of the electron Fermi surface in the cobaltates, and qualitatively reproduce the essential feature of the evolution of the electron Fermi surface with doping. It is shown that the underlying hexagonal electron Fermi surface obeys Luttinger's theorem. The theory also predicts a Fermi-arc phenomenon at the low-doped regime, where the region of the hexagonal electron Fermi surface along the [Formula: see text]-K direction is suppressed by the electron self-energy, and then six disconnected Fermi arcs located at the region of the hexagonal electron Fermi surface along the [Formula: see text]-M direction emerge. However, this Fermi-arc phenomenon at the low-doped regime weakens with the increase of doping.

  15. FAST: a three-dimensional time-dependent FEL simulation code

    CERN Document Server

    Saldin, E L; Yurkov, M V

    1999-01-01

    In this report we briefly describe the three-dimensional, time-dependent FEL simulation code FAST. The equations of motion of the particles and Maxwell's equations are solved simultaneously taking into account the slippage effect. Radiation fields are calculated using an integral solution of Maxwell's equations. A special technique has been developed for fast calculations of the radiation field, drastically reducing the required CPU time. As a result, the developed code allows one to use a personal computer for time-dependent simulations. The code allows one to simulate the radiation from the electron bunch of any transverse and longitudinal bunch shape; to simulate simultaneously an external seed with superimposed noise in the electron beam; to take into account energy spread in the electron beam and the space charge fields; and to simulate a high-gain, high-efficiency FEL amplifier with a tapered undulator. It is important to note that there are no significant memory limitations in the developed code and an...

  16. Self-seeding scheme with gas monochromator for narrow-bandwidth soft X-ray FELs

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2011-01-01

    Self-seeding schemes, consisting of two undulators with a monochromator in between, aim at reducing the bandwidth of SASE X-ray FELs. We recently proposed to use a new method of monochromatization exploiting a single crystal in Bragg-transmission geometry for self-seeding in the hard X-ray range. Here we consider a possible extension of this method to the soft X-ray range using a cell filled with resonantly absorbing gas as monochromator. The transmittance spectrum in the gas exhibits an absorbing resonance with narrow bandwidth. Then, similarly to the hard X-ray case, the temporal waveform of the transmitted radiation pulse is characterized by a long monochromatic wake. In fact, the FEL pulse forces the gas atoms to oscillate in a way consistent with a forward-propagating, monochromatic radiation beam. The radiation power within this wake is much larger than the equivalent shot noise power in the electron bunch. Further on, the monochromatic wake of the radiation pulse is combined with the delayed electron b...

  17. Normal-conducting RF cavity of high current photoinjector for high power CW FEL.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Schultheiss, T. (Thomas); Rathke, J. (John); Young, L. M. (Lloyd M.)

    2004-01-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, {pi}-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With the electric field gradients of 7.7, and 5 MV/m in the three cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and the transverse rms emittance 7 mm-mrad. Electromagnetic modeling was used extensively to optimize ridge-loaded tapered waveguides and RF couplers, which led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. The manufacturing of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher power levels by increasing the electron bunch repetition rate, and provides a path to a MW-class amplifier FEL. This paper presents the cavity design and details of RF coupler modeling.

  18. Normal conducting RF cavity of high current photoinjector for high power CW FEL.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey); Schrage, D. L. (Dale L.); Wood R. L. (Richard L.); Schultheiss, T. (Thomas); Rathke, J. (John); Christina, V.; Young, L. M. (Lloyd M.)

    2004-01-01

    An RF photoinjector capable of producing high continuous average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell {pi}-mode 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With the electric field gradients of 7, 7, and 5 MV/m in the three cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and 7 mm-mrad transverse rms emittance. Electromagnetic modeling was used extensively to optimize ridge-loaded tapered waveguides and RF couplers, which led to a new improved coupler-iris design. The results, combined with a thermal/stress analysis, show that the challenging problem of cavity cooling can be successfully solved. A demo 100-mA (at 35-MHz bunch-repetition rate) photoinjector is being manufactured. The design is scalable to higher power levels by increasing the bunch repetition rate, and provides a path to a MW-class amplifier FEL. The cavity design and details of RF coupler modeling are presented.

  19. Normal-Conducting High Current RF Photoinjector for High Power CW FEL

    CERN Document Server

    Kurennoy, Sergey; Nguyen, Dinh C; Rathke, John; Schrage, Dale L; Schultheiss, Tom; Wood, Richard L; Young, Lloyd M

    2005-01-01

    An RF photoinjector capable of producing high average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, pi-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With average gradients of 7, 7, and 5 MV/m in its three accelerating cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and transverse rms emittance below 7 mm-mrad. Electromagnetic modeling has been used extensively to optimize ridge-loaded tapered waveguides and RF couplers, and led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. Fabrication of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher average currents by increasing the electron bunch repetition rate, and provides a path to a MW-class FEL. This p...

  20. Investigation of short pulse effects in IR FELs and new simulation results

    CERN Document Server

    Asgekar, Vivek; Brunken, M; Casper, Lars; Genz, Harald; Grigore, Maria; Hessler, Christoph; Khodyachykh, Sergiy; Richter, Achim; Van der Meer, Alex F G

    2003-01-01

    The Darmstadt IR FEL is designed to generate wavelengths between 3 and 10 mum and driven by the superconducting electron linear accelerator. The pulsed electron beam has a peak current of 2.7 A leading to a small signal gain of 5%. Currently, investigations of the energy transfer process inside the undulator are performed using the 1D time-dependent simulation code FAST1D-OSC. We present simulation results for the power vs. different desynchronization and tapering parameters as well as a comparison with experimental data from the S-DALINAC IR-FEL. Furthermore, a compact autocorrelation system assuring a background-free measurement of the optical pulse length is described. In a first test experiment at FELIX, the autocorrelator has been tested at wavelengths 5.7 less than approximately equals lambda less than approximately equals 9.0 mum. The frequency doubling in a 2 mm-long ZnGeP//2-crystal resulted in a time resolution of 300 fs and a conversion efficiency of 5%.

  1. Production and detection of axion-like particles at the VUV-FEL. Letter of intent

    Energy Technology Data Exchange (ETDEWEB)

    Koetz, U.; Ringwald, A.; Tschentscher, T.

    2006-06-15

    Recently, the PVLAS collaboration has reported evidence for an anomalously large rotation of the polarization of light generated in vacuum in the presence of a transverse magnetic field. This may be explained through the production of a new light spin-zero particle coupled to two photons. In this Letter of Intent, we propose to test this hypothesis by setting up a photon regeneration experiment which exploits the photon beam of the Vacuum-UltraViolet Free-Electron Laser VUV-FEL, sent along the transverse magnetic field of a linear arrangement of dipole magnets of size B L {approx} 30 Tm. The high photon energies available at the VUV-FEL increase substantially the expected photon regeneration rate in the mass range implied by the PVLAS anomaly, in comparison to the rate expected at visible lasers of similar power. We find that the particle interpretation of the PVLAS result can be tested within a short running period. The pseudoscalar vs. scalar nature can be determined by varying the direction of the magnetic field with respect to the laser polarization. The mass of the particle can be measured by running at different photon energies. The proposed experiment offers a window of opportunity for a firm establishment or exclusion of the particle interpretation of the PVLAS anomaly before other experiments can compete. (Orig.)

  2. Growth of nano-dots on the grazing-incidence mirror surface under FEL irradiation.

    Science.gov (United States)

    Kozhevnikov, I V; Buzmakov, A V; Siewert, F; Tiedtke, K; Störmer, M; Samoylova, L; Sinn, H

    2016-01-01

    A new phenomenon on X-ray optics surfaces has been observed: the growth of nano-dots (40-55 nm diameter, 8-13 nm height, 9.4 dots µm(-2) surface density) on the grazing-incidence mirror surface under irradiation by the free-electron laser (FEL) FLASH (5-45 nm wavelength, 3° grazing-incidence angle). With a model calculation it is shown that these nano-dots may occur during the growth of a contamination layer due to polymerization of incoming hydrocarbon molecules. The crucial factors responsible for the growth of nano-dots in the model are the incident peak intensity and the reflection angle of the beam. A reduction of the peak intensity (e.g. replacement of the FEL beam by synchrotron radiation) as well as a decrease of the incident angle by just 1° (from 3° to 2°) may result in the total disappearance of the nano-dots. The model calculations are compared with surface analysis of two FLASH mirrors.

  3. Design considerations of 10 kW-scale, extreme ultraviolet SASE FEL for lithography

    CERN Document Server

    Pagani, C; Schneidmiller, E A; Yurkov, M V

    2001-01-01

    The semiconductor industry growth is driven to a large extent by steady advancements in microlithography. According to the newly updated industry road map, the 70 nm generation is anticipated to be available in the year 2008. However, the path to get there is not clear. The problem of construction of extreme ultraviolet (EUV) quantum lasers for lithography is still unsolved: progress in this field is rather moderate and we cannot expect a significant breakthrough in the near future. Nevertheless, there is clear path for optical lithography to take us to sub-100 nm dimensions. Theoretical and experimental work in Self-Amplified Spontaneous Emission (SASE) Free Electron Lasers (FEL) physics and the physics of superconducting linear accelerators over the last 10 years has pointed to the possibility of the generation of high-power optical beams with laser-like characteristics in the EUV spectral range. Recently, there have been important advances in demonstrating a high-gain SASE FEL at 100 nm wavelength (J. Andr...

  4. Three-dimensional Simulation of Thermal Harmonic Lasing FEL with Detuning of the Fundamental

    CERN Document Server

    Salehi, Elham; Mirian, Najmeh Sadat

    2016-01-01

    Detuning of the fundamental is a way to enhance harmonic generation . By this method, the wiggler is composed of two segments in such a way that the fundamental resonance of the second segment to coincide with the third harmonic of the first segment of the wiggler to generate extreme ultraviolet radiation and x-ray emission. A set of coupled, nonlinear, and first-order differential equations in three dimensions describing the evolution of the electron trajectories and the radiation field with warm beam is solved numerically by CYRUS 3D code in the steady-state for two models (1) seeded free electron laser (FEL) and (2) shot noise on the electron beam (self-amplified spontaneous emission FEL). Thermal effects in the form of longitudinal velocity spread is considered. Three-dimensional simulation describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes are investigated...

  5. VUV/Soft X-Ray FEL Projects on the Horizon

    CERN Document Server

    Bakker, Rene J

    2005-01-01

    Free-Electron Lasers (FELs) combine the properties of lasers and synchrotron radiation: the possibility to produce high-power, short-pulsed, laser-like radiation in spectral regions not accessible by other light-sources. Operation of an FEL in the Vacuum Ultra Violet (VUV) to X-ray spectral region has proven challenging, however, mainly because of the increased demands set to the accelerator technology as the wavelength becomes shorter (higher peak currents and beam energy, combined with a high stability and a lower emittance and/or energy spread). Over the last decade many of these challenges have been addressed and several laboratories have demonstrated successful operation from the Infrared to the VUV. These results are very significant as they pave the way to the construction of the next-generation light-sources. Moreover, they have demonstrated the validity of the tools used to design and predict performances of such devices at these-, or ever shorter wavelengths. This presentation gives an overview of t...

  6. Optical alignment and tuning system for the HUST THz-FEL

    Science.gov (United States)

    Liu, Xu; Liu, Kaifeng; Qin, Bin; Tan, Ping; Fu, Qiang; Wang, Wei; Pei, Yuanji

    2016-11-01

    A compact FEL oscillator with a radiation wavelength of 30 - 100 μm is proposed by HUST and NSRL. The optical cavity is very sensitive to misalignment errors of the mirror, due to its near-concentric and symmetric structure. The magnetic axis of the undulator, the optical axis of the resonator, and the electron beam propagation axis must all be aligned with high precision for achieving saturated lasing. This paper introduces a high-precision, multi-degree-of-freedom controlled optical alignment system, which has the ability to align in the transverse and longitudinal directions. The alignment tolerances are given by theoretical analysis and numerical simulations with three-dimensional FEL code GENESIS and optical propagation code (OPC). To accomplish optical alignment, two auxiliary HeNe laser systems were introduced. By adjusting the HeNe laser beam spot on the wedge, the optical axis can be aligned to the magnetic axis, and the estimated errors meet the tolerances. Finally, the electron beam will be guided through the hole in the central wedge to complete the transverse alignment. The longitudinal alignment and tuning methods are also described.

  7. Application of the green function formalism to nonlinear evolution of the low gain FEL oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Shvets, G. [Princeton Plasma Physics Lab., NJ (United States); Wurtele, J.S.; Gardent, D. [Massachusetts Institute of Technology, Cambridge, MA (United States)] [and others

    1995-12-31

    A matrix formalism for the optical pulse evolution in the frequency domain, is applied to the nonlinear regime of operation. The formalism was previously developed for studies of the linear evolution of the low-gain FEL oscillator with an arbitrary shape of the electron beam. By varying experimentally controllable parameters, such as cavity detunning and cavity losses, different regimes of operation of the FEL oscillator, such as a steady state saturation and limit cycle saturation, are studied numerically. It is demonstrated that the linear supermodes, numerically obtained from the matrix formalism, provide an appropriate framework for analyzing the periodic change in the output power in the limit cycle regime. The frequency of this oscillation is related to the frequencies of the lowest-order linear supermodes. The response of the output radiation to periodic variation of the electron energy is studied. It is found that the response is enhanced when the frequency of the energy variation corresponds to the difference of per-pass phase advances of the lowest linear supermodes. Finally, various nonlinear models are tested to capture the steady state saturation and limit cycle variation of the EM field in the oscillator cavity.

  8. Comments on advanced, time-resolved imaging techniques for free-electron laser (FEL) experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.

    1992-01-01

    An extensive set of time-resolved imaging experiments has been performed on rf-linac driven free-electron lasers (FELs) over the past few years. These experiments have addressed both micropulse and macropulse timescales on both the charged-particle beam and the wiggler/undulator outputs (spontaneous emission and lasing). A brief review of first measurements on photoinjecter micropulse elongation, submacropulse phase slew in drive lasers, submacropulse wavelength shifts in lasers, etc. is presented. This is followed by discussions of new measurements of 35-MeV electron beam micropulse bunch length (<10 ps) using optical transition radiation, some of the first single bend synchrotron radiation beam profile measurements at gamma <80, and comments on the low-jitter synchroscan streak camera tuner. These techniques will be further developed on the 200-650 MeV linac test stand at the Advanced Photon Source (APS) in the next few years. Such techniques should be adaptable to many of the present FEL designs and to some aspects of the next generation of light sources.

  9. Comments on advanced, time-resolved imaging techniques for free-electron laser (FEL) experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.

    1992-11-01

    An extensive set of time-resolved imaging experiments has been performed on rf-linac driven free-electron lasers (FELs) over the past few years. These experiments have addressed both micropulse and macropulse timescales on both the charged-particle beam and the wiggler/undulator outputs (spontaneous emission and lasing). A brief review of first measurements on photoinjecter micropulse elongation, submacropulse phase slew in drive lasers, submacropulse wavelength shifts in lasers, etc. is presented. This is followed by discussions of new measurements of 35-MeV electron beam micropulse bunch length (<10 ps) using optical transition radiation, some of the first single bend synchrotron radiation beam profile measurements at gamma <80, and comments on the low-jitter synchroscan streak camera tuner. These techniques will be further developed on the 200-650 MeV linac test stand at the Advanced Photon Source (APS) in the next few years. Such techniques should be adaptable to many of the present FEL designs and to some aspects of the next generation of light sources.

  10. Performance of an undulator for visible and UV FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Miyauchi, Y.; Zako, A.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two infrared free electron lasers (FELs) of the FELI project are now operating in the wavelength range of 1-20{mu}m. A 2.68-m undulator has been constructed for visible and UV FELs covering the wavelength of 1-0.2{mu}m for 100-165 MeV electron beams. It generates alternating, horizontal magnetic field, and wiggles electron beam on a vertical plane. The undulator length and period are 2.68m and 40mm, respectively. The gap of undulator magnets can be changed remotely by using servomotors with an accuracy of 1 {mu}m from the control room. The maximum K-value and related magnetic field strength are 1.9 and 0.5T, respectively, when its gap is set to the minimum value of 16mm. In order to minimize magnetic field reduction due to radiation damage, Sm-Co permanent magnet was adopted. Its structure and the results of magnetic field measurement will be reported.

  11. 3 kA Power Supplies for the Duke OK-5 FEL Wigglers

    CERN Document Server

    Popov, Victor; Mikhailov, Stepan; Oakeley, Owen; Wallace, Patrick W; Wu, Y K

    2005-01-01

    The next generation electromagnetic OK-5/Duke storage ring FEL wigglers require three 3kA/70V power supplies with current stability about 20 ppm and current ripples less than 20ppm in their full operating range. Duke FEL Laboratory acquired three out-of-service thyristor controllable power supplies (Transrex, 5kA/100V) which was built almost 30 years ago. The existing archaic firing circuit, lack of any output voltage filtering and outdated DCCT, would not be able to meet the above requirements.To deliver the desirable high performance with very limited funds, all three T-Rex power supplies have been completely rebuilt in house at DFELL. Modern high stability electronic components and a Danfysik DCCT with a high current stability have been used. New symmetrical firing circuit, efficient passive LC filter and reliable transformer-coupled active filter are used to reduce output current ripples to an appropriate level. At the present time, the first refurbished power supply in operation since August, 2004 with g...

  12. Optical Observations Of Fermi LAT Monitored Blazars

    Science.gov (United States)

    Cook, Kyle; Carini, M. T.

    2009-01-01

    For the past 8 years the Bell Observatory at Western Kentucky University has been conducting R band monitoring of the variability of approximately 50 Blazars. A subset of these objects are being routinely observed with the LAT instrument on-board the Fermi Space Telescope. Adding the Robotically Controlled Telescope (RCT) at Kitt Peak National Observatory and observations with the AZT-11 telescope at the Crimean Astrophysical Observatory (CRAO), we are intensively monitoring the Blazars on the Lat monitoring list. We present the results of our long term monitoring of the LAT monitored Blazars, as well as the recent contemporaneous optical R band observations we have obtained of the LAT Blazars.

  13. Shear Viscosity of a Unitary Fermi Gas

    OpenAIRE

    Wlazłowski, Gabriel; Magierski, Piotr; Drut, Joaquín E.

    2012-01-01

    We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates...

  14. -Rays Radiation of High Redshift Fermi Blazars

    Indian Academy of Sciences (India)

    W. G. Liu; S. H. Fu; X. Zhang; L. Ma; Y. B. Li; D. R. Xiong

    2014-09-01

    Based on the 31 high redshift ( > 2) Flat Spectral Radio Quasars (FSRQs), which is from the second Fermi-LAT AGNs catalogue (2LAC), we studied the correlation between flux densities (R, K, ) in the radio, infrared and -ray wave bands. We found that there is a significant positive correlation between and R, and a weak anticorrelation between and K in the average state. For high redshift blazars, we argue that the seed photon of -ray emission mainly comes from the jet itself and partially from the dusty torus.

  15. Emergent physics: Fermi-point scenario.

    Science.gov (United States)

    Volovik, Grigory

    2008-08-28

    The Fermi-point scenario of emergent gravity has the following consequences: gravity emerges together with fermionic and bosonic matter; emergent fermionic matter consists of massless Weyl fermions; emergent bosonic matter consists of gauge fields; Lorentz symmetry persists well above the Planck energy; space-time is naturally four dimensional; the Universe is naturally flat; the cosmological constant is naturally small or zero; the underlying physics is based on discrete symmetries; 'quantum gravity' cannot be obtained by quantization of Einstein equations; and there is no contradiction between quantum mechanics and gravity, etc.

  16. Bragg spectroscopy of strongly interacting Fermi gases

    Science.gov (United States)

    Lingham, M. G.; Fenech, K.; Peppler, T.; Hoinka, S.; Dyke, P.; Hannaford, P.; Vale, C. J.

    2016-10-01

    This article provides an overview of recent developments and emerging topics in the study of two-component Fermi gases using Bragg spectroscopy. Bragg scattering is achieved by exposing a gas to two intersecting laser beams with a slight frequency difference and measuring the momentum transferred to the atoms. By varying the Bragg laser detuning, it is possible to measure either the density or spin response functions which characterize the basic excitations present in the gas. Specifically, one can measure properties such as the dynamic and static structure factors, Tan's universal contact parameter and observe signatures for the onset of pair condensation locally within a gas.

  17. Holographic non-Fermi-liquid fixed points.

    Science.gov (United States)

    Faulkner, Tom; Iqbal, Nabil; Liu, Hong; McGreevy, John; Vegh, David

    2011-04-28

    Techniques arising from string theory can be used to study assemblies of strongly interacting fermions. Via this 'holographic duality', various strongly coupled many-body systems are solved using an auxiliary theory of gravity. Simple holographic realizations of finite density exhibit single-particle spectral functions with sharp Fermi surfaces, of a form distinct from those of the Landau theory. The self-energy is given by a correlation function in an infrared (IR) fixed-point theory that is represented by a two-dimensional anti de Sitter space (AdS(2)) region in the dual gravitational description. Here, we describe in detail the gravity calculation of this IR correlation function.

  18. Search of the Earth Limb Fermi Data and Non-Galactic Center Region Fermi Data for Signs of Narrow Lines

    CERN Document Server

    Bloom, E; Izaguirre, E; Snyder, A; Albert, A; Winer, B; Yang, Z; Essig, R

    2013-01-01

    Since the spring of 2012 there have been many papers published using Fermi LAT public data that claim evidence for narrow spectral lines coming from the region of the Galactic center. This study uses non-Galactic center Fermi-LAT data from survey mode observations, and Earth limb Fermi data to test the dark matter interpretation of this feature and better understand its origins.

  19. Spiraling Fermi arcs in Weyl materials

    Science.gov (United States)

    Li, Songci; Andreev, Anton

    In Weyl materials the valence and conduction electron bands touch at an even number of isolated points in the Brillouin zone. In the vicinity of these points the electron dispersion is linear and may be described by the massless Dirac equation. This results in nontrivial topology of Berry connection curvature. One of its consequences is the existence of peculiar surface electron states whose Fermi surfaces form arcs connecting projections of the Weyl points onto the surface plane. Band bending near the boundary of the crystal also produces surface states. We show that in Weyl materials band bending near the crystal surface gives rise to spiral structure of energy surfaces of arc states. The corresponding Fermi surface has the shape of a spiral that winds about the projection of the Weyl point onto the surface plane. The direction of the winding is determined by the helicity of the Weyl point and the sign of the band bending potential. For close valleys arc state morphology may be understood in terms of avoided crossing of oppositely winding spirals. This work is supported by the U.S. Department of Energy Office of Science, Basic Energy Sciences under Award Number DE-FG02-07ER46452.

  20. Fermi Acceleration in Magnetic Reconnection Sites

    Science.gov (United States)

    de Gouveia Dal Pino, E. M.; Kowal, G.; Lazarian, A.

    2014-09-01

    The mechanisms that accelerate cosmic relativistic particles are not fully understood yet. A variety of processes has been investigated and the acceleration in magnetic reconnection sites has lately gained increasing attention from researchers not only for its potential importance in the solar system, but also beyond it, in astrophysical environments like compact stellar sources, AGNs and GRBs, and even in diffusive magnetized media as the interstellar medium (ISM) and the intergalactic medium (IGM). In this talk we review this process and, supported by three-dimensional MHD simulations with the injection of thousands of test particles, we show that they can be efficiently accelerated by magnetic reconnection through a first-order Fermi process within large scale magnetic current sheets, even in a collisional fluid (contrary to what was previously believed), especially when local turbulence is present which makes reconnection fast, the acceleration layer thicker and the overall process naturally three-dimensional. Tests of particle acceleration in pure MHD turbulent environments (i.e., without the presence of large scale current sheets), on the other hand, indicate that the dominant acceleration process is a second-order Fermi.