Keyword: FEL
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MOYCA01 Status Report on the Commissioning of the Japanese XFEL at SPring-8 laser, undulator, acceleration, electron 21
 
  • H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  The Japanese XFEL at SPring-8, which was named SACLA (Spring-8 Angstrom Compact free electron LAser), was completed in FY2010. After RF full-power aging for about four months the beam commissioning of SACLA has been started since 21 February 2011. About one month later, in 23 March a design beam energy of 8 GeV was achieved and a spontaneous undulator radiation of 0.8 Angstrom was observed at the beam-line optical hutch by closing XFEL undulator gaps down to 5 mm in full-width. The beam commissioning has proceeded smoothly and since the middle of April we have entered to a tuning phase towards SASE lasing, which is at least one month ahead of schedule. This talk will report the beam commissioning overview of SACLA including SASE XFEL performance, key tuning-processes and critical issues for achieving the lasing.  
slides icon Slides MOYCA01 [37.840 MB]  
 
MOOCB02 Commissioning and Performance of the Beam Monitor System for XFEL/SPring-8 “SACLA” cavity, electron, undulator, bunching 47
 
  • Y. Otake, C. Kondo, H. Maesaka
    RIKEN Spring-8 Harima, Hyogo, Japan
  • H. Ego, S. Matsubara, T. Matsumoto, T. Sakurai, H. Tomizawa, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  • S.I. Inoue
    SES, Hyogo-pref., Japan
  
  The construction of a beam monitor system for XFEL/SPring 8 “SACLA” was completed. The system was developed to realize a spatial resolution of less than 3 um to align a beam orbit for an undulator section with about 100 m long and a temporal resolution to measure bunch lengths from 1 ns to 30 fs to maintain a constant peak beam current conducting stable SASE lasing. The system principally comprises cavity type beam position monitors (BPM), current monitors (CT), screen monitors (SCM) and bunch length measurement instruments, such as an rf deflector and CSR detectors. Commissioning of SACLA started from March 2011, and the monitors performed sufficient roles to tune beams for the lasing. The achieved over-all performances of the system including DAQ are: the BPM have spatial resolution of 300 nm, the bunch length monitors observe bunch lengths from 1ns in an injector with velocity bunching to less than 30 fs after three-stage bunch compressors. The less than a 3 um spatial resolution of the SCM was also confirmed in practical beam operation. By these fulfilled performances, the stable lasing of SACLA will be achieved. This report describes commissioning, performance of the system.  
slides icon Slides MOOCB02 [7.516 MB]  
 
MOPC012 Fabrication of the CERN/PSI/ST X-band Accelerating Structures wakefield, alignment, vacuum, coupling 86
 
  • M.M. Dehler, A. Citterio, R. Zennaro
    PSI, Villigen, Switzerland
  • S. Atieh, D. Gudkov, S. Lebet, G. Riddone, J. Shi
    CERN, Geneva, Switzerland
  • G. D'Auria, C. Serpico
    ELETTRA, Basovizza, Italy
  
  Within a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a multi- purpose X-band accelerating structure has been designed and fabricated, used for high gradients tests in the CLIC structure testing program and in the FEL projects of PSI and ST. The structure has 72 cells with a phase advance of 5 pi/6 and includes upstream and downstream wakefield monitors to measure the beam alignment. The SLAC mode launcher design is used to feed it with RF power. Following the CERN fabrication procedures for high-gradient structure, diffusion bonding and brazing in hydrogen atmosphere is used to assemble the cells. After tuning, a vacuum bakeout is required before the feedthroughs for the wake field monitors are welded in as a last step. We describe the experiences gained in finishing the first two structures out of a series of four and present the results from the RF tuning and low level RF tests.  
 
MOPC013 Design, Fabrication and High Power RF Test of a C-band Accelerating Structure for Feasibility Study of the SPARC Photo-injector Energy Upgrade accelerating-gradient, impedance, klystron, radiation 89
 
  • D. Alesini, R. Boni, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo, F. Marcellini
    INFN/LNF, Frascati (Roma), Italy
  • G. Campogiani, A. Mostacci, L. Palumbo, S. Persichelli, V. Spizzo
    Rome University La Sapienza, Roma, Italy
  • T. Higo, K. Kakihara, S. Matsumoto
    KEK, Ibaraki, Japan
  • S. Verdú-Andrés
    TERA, Novara, Italy
  
  The energy upgrade of the SPARC photo-injector from 170 to 250 MeV will be done by replacing a low gradient 3m S-Band structure with two 1.5m high gradient C-band structures. The structures are traveling wave, constant impedance sections, have symmetric waveguide input couplers and have been optimized to work with a SLED RF input pulse. A prototype with a reduced number of cells has been fabricated and tested at high power in KEK (Japan) giving very good performances in terms of breakdown rates at high accelerating gradient (>50 MV/m). The paper illustrates the design criteria of the structures, the fabrication procedure and the high power RF test results.  
 
MOPC029 Development of Injector for Compact FEL Tera-hertz Source in CAEP gun, electron, booster, simulation 131
 
  • W. Bai, M. Li, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  This paper introducs the development of a injector for compact FEL tera-hertz source at Institute of Applied Electronics in China Academy of Engineering Physics (IAE/CAEP). The injector consist of a main accelerator for energy booster section and a multicavity thermionic-cathode rf gun with low back bombardment, with total length no more than one meter. Numerical simulation result shows that the back bombardment power is less for the thermionic-cathode rf gun of the injector and the main accelerator has a good performance, which can provide high quality electron beam with emittance about 10 pi mm mrad, energy about 7 MeV and energy spread about 1%. At present, the preliminary hot test experiment on the injector has been done. The test results indicate that the mainly tested parameters agree well with the theoretical design ones. The process of the preliminary hot test experiment on the injector is present in this paper.  
 
MOPC144 Autocorrelation Function and Power Spectrum of a Train of Quasiperiodic Sequence of Pulses electron, wakefield, free-electron-laser, optics 415
 
  • E.M. Laziev, B. Grigoryan, V.M. Tsakanov
    CANDLE, Yerevan, Armenia
  • M. Movsisyan, D.L. Oganesyan
    YSU, Yerevan, Armenia
  
  The statistical relationship of the autocorrelation function and spectrum of a train of quasi-periodic sequence of pulses having a time jitter of the repetition rate is obtained. Presented the accordance of autocorrelation function as well as power spectrum of the bounded quasi-periodic sequence of pulses and timing jitter of their repetition rate. The results can be used at the measurements of timing jitter of a train of electron bunches.  
 
MOPC148 Optical Clock Distribution System at the ALICE Energy Recovery Linac pick-up, laser, electron, feedback 427
 
  • T.T. Ng, S.P. Jamison
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Highly stable clock distribution across future light sources is important for the synchronisation of beam generation, manipulation and diagnostics with photon experiments. Optical fibre technology can be used to combat the stability challenges in distributing clock signals over long distances with coaxial cable. We report here on the status of the optical clock distribution system installed on the ALICE energy recovery linac which uses the propagation of ultra-short optical pulses to carry the clock signal. We also present the characterisation of a beam arrival monitor suitable using <40 pC bunch charges and 7 mW, sub-100 fs distributed clock pulses.  
 
MOPS085 Wakefield Calculations for the LCLS in Multibunch Operation* linac, dipole, injection, HOM 802
 
  • K.L.F. Bane
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.
Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well*, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode. The longitudinal wake changes the average energy and chirp at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse.
* F.-J. Decker et al, "A demonstration of multi-bunch operation in the LCLS," Proceedings of FEL2010, Malmoe, Sweden, p. 467. 		 
 
TUZA01 Commissioning and Initial Operation of FERMI@Elettra electron, laser, photon, undulator 918
 
  • S. Di Mitri, E. Allaria, R. Appio, L. Badano, S. Bassanese, F. Bencivenga, A.O. Borga, M. Bossi, E. Busetto, C. Callegari, F. Capotondi, K. Casarin, D. Castronovo, P. Cinquegrana, D. Cocco, M. Cornacchia, P. Craievich, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, P. Delgiusto, A.A. Demidovich, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, S. Ferry, V. Feyer, L. Fröhlich, P. Furlan Radivo, G. Gaio, F. Gelmetti, L. Giannessi, R. Gobessi, R. Ivanov, E. Karantzoulis, M. Kiskinova, M. Lonza, A.A. Lutman, C. Masciovecchio, R.H. Menk, M.M. Milloch, M.M. Musardo, I. Nikolov, S. Noe, F. Parmigiani, L. Pavlovič, E. Pedersoli, G. Penco, M. Petronio, M. Predonzani, E. Principi, E. Quai, G. Quondam, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Wang, M. Zaccaria, D. Zangrando
    ELETTRA, Basovizza, Italy
  • M. Alagia, A. Kivimaki, M. Zangrando, M. de Simone
    IOM-CNR, Trieste, Italy
  • L. Avaldi, P. Bolognesi, M. Coreno, P. O’Keeffe
    CNR - IMIP, Trieste, Italy
  • M. Dal Forno
    DIEIT, Trieste, Italy
  • G. De Ninno, S. Spampinati
    University of Nova Gorica, Nova Gorica, Slovenia
  • M. Devetta, T. Mazza, P. Piseri
    Università degli Studi di Milano, Milano, Italy
  • E. Ferrari
    Università degli Studi di Trieste, Trieste, Italy
  • S. Stranges
    Università di Roma "La Sapienza", Roma, Italy
  
  Funding: Work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3.
This article describes the design goals of FERMI@Elettra, reports on the goals achieved so far and shows how the facility development has been driven by the new research frontier of ultra-fast, extreme ultra-violet and soft X-ray science. The commissioning phases and first experience with user pilot experiments are presented and discussed. 		 
slides icon Slides TUZA01 [13.401 MB]  
 
TUZA02 sFLASH - Present Status and Commissioning Results undulator, electron, laser, radiation 923
 
  • V. Miltchev, S. Ackermann, A. Azima, J. Bödewadt, F. Curbis, M. Drescher, E. Hass, Th. Maltezopoulos, M. Mittenzwey, J. Rönsch-Schulenburg, J. Roßbach, R. Tarkeshian
    Uni HH, Hamburg, Germany
  • H. Delsim-Hashemi, K. Honkavaara, T. Laarmann, H. Schlarb, S. Schreiber, M. Tischer
    DESY, Hamburg, Germany
  • R. Ischebeck
    PSI, Villigen, Switzerland
  • S. Khan
    DELTA, Dortmund, Germany
  
  The free-electron laser in Hamburg (FLASH) was previously being operated in the self-amplified spontaneous emission (SASE) mode, producing photons in the XUV wavelength range. Due to the start-up from noise the SASE-radiation consists of a number of uncorrelated modes, which results in a reduced coherence. One option to simultaneously improve both the coherence and the synchronisation between the FEL-pulse and an external laser is to operate FLASH as an amplifier of a seed produced using high harmonics generation (HHG). An experimental set-up - sFLASH, has been installed to test this concept for the wavelengths below 40 nm. The sFLASH installation took place during the planed FLASH shutdown in the winter of 2009/2010. The technical commissioning, which began in the spring of 2010, has been followed by seeded-FEL commissioning, FEL-characterisation and pilot experiments. In this contribution the present status and the sFLASH commissioning results will be discussed.  
slides icon Slides TUZA02 [4.125 MB]  
 
TUODA03 The Status of the ALICE Accelerator R&D Facility at STFC Daresbury Laboratory radiation, cavity, electron, diagnostics 934
 
  • F. Jackson, D. Angal-Kalinin, R. Bate, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, D.J. Dunning, J.-L. Fernández-Hernando, A.R. Goulden, S.F. Hill, D.J. Holder, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, S. Leonard, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, A.J. Moss, B.D. Muratori, T.T. Ng, J.F. Orrett, S.M. Pattalwar, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, A.D. Smith, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Harrison, G.M. Holder, A.L. Schofield, P. Weightman, R.L. Williams, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • M. Surman
    STFC/DL/SRD, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Science and Technology Facilities Council
The ALICE accelerator, the first energy recovery machine in Europe, has recently demonstrated lasing of an infra-red free electron laser (IR-FEL). The current status of the machine and recent developments are described. These include: lasing of the IR-FEL, a programme of powerful coherent terahertz radiation research, electro-optic diagnostic techniques, development of high precision timing and distribution system, implementation of digital low level RF control. ALICE also serves as an injector for the EMMA non-scaling FFAG machine. 		 
slides icon Slides TUODA03 [1.648 MB]  
 
TUPC009 The Recent JINR Advances in Technology Development on Linear Accelerators laser, electron, radiation, cryomodule 1006
 
  • G. Shirkov, N. Balalykin, A. Dudarev, E. Syresin, G.V. Trubnikov, Yu.A. Yulian
    JINR, Dubna, Moscow Region, Russia
  • E. Khazanov
    IAP/RAS, Nizhny Novgorod, Russia
  
  JINR experts take part in a few ILC related projects including photo injector prototype, participation in design and construction of cryomodules, RND on design of a new version of superconducting niobium resonator, laser metrology, etc. Some new results of this activity as well as recent data of ILC siting investigations in the Dubna region are presented.  
 
TUPC093 CSR Bunch Length Monitor for XFEL/SPring-8 - SACLA radiation, electron, synchrotron, synchrotron-radiation 1224
 
  • C. Kondo, S. Matsubara, T. Matsumoto
    JASRI/SPring-8, Hyogo-ken, Japan
  • S.I. Inoue, H. Maesaka, Y. Otake
    RIKEN Spring-8 Harima, Hyogo, Japan
  
  SPring-8 Angstrom Compact Free Electron Laser (SACLA) is now under commissioning operation, aimed at the generation of a sub-angstrom free electron laser (FEL). In order to ensure the stable FEL generation, non-distractive bunch length monitors utilizing coherent synchrotron radiation (CSR) are installed. The monitors are located at the downstream of individual bunch compressor (BC1-BC3), and they measure the radiation emitted at the individual last magnets of the chicanes. At the magnets, beams with bunch lengths form 10 fs to 1000 fs generate the CSRs with a spectrum ranging the almost whole infrared region (0.03 - 3 THz). The CSRs are detected by a Schottky diode at the BC1, or pyroelectric detectors and a simple organic lens optical system at BC2 and 3. The bunch length monitor systems are used for bunch length feedback control to obtain the stable lasing by changing the rf parameter of acceleration cavities before the BCs. A preliminary system for the above mentioned system was tested at the SCSS test accelerator, and it showed sufficient performance to measure bunch length up to 300 fs. In this report, we describe the design and the results of the first operation.  
 
TUPC121 Development of MCP Based Photon Detectors for the European XFEL photon, radiation, background, vacuum 1299
 
  • E. Syresin, M.N. Kapishin
    JINR, Dubna, Moscow Region, Russia
  • O.I. Brovko, A.V. Shabunov
    JINR/VBLHEP, Moscow, Russia
  • W. Freund, J. Grünert, H. Sinn
    European XFEL GmbH, Hamburg, Germany
  • M.V. Yurkov
    DESY, Hamburg, Germany
  
  To provide successful operation of SASE XFEL the radiation detectors should operate in wide dynamic range from the level of spontaneous emission to the saturation level, in wide wavelength range from 0.05 nm to 0.16 nm for SASE1 and SASE2 and from 0.4 nm to 4.4 nm for SASE3. High relative accuracy of measurements is crucial for detection of a signature of lasing, tuning of amplification process, and characterization of statistical properties of the radiation. The XFEL radiation detector based on micro-channel plates (MCP) meets these requirements. Two types of the photon detector are used for measurements of the pulse radiation energy and the image of the photon beam. The dynamic range of photon pulse energies is between 1 nJ and 10 mJ. This applies to spontaneous and FEL radiation. The relative accuracy of pulse energy measurements is better than 1%. The visualization of a single bunch in a train, or average image over the full train will perform by the MCP imager at a spatial resolution of 30 μm.  
 
TUPO018 Self-stimulated Undulator Klystron undulator, electron, kicker, storage-ring 1482
 
  • E.G. Bessonov, A.L. Osipov
    LPI, Moscow, Russia
  • A.A. Mikhailichenko
    CLASSE, Ithaca, New York, USA
  
  The Self Stimulated Undulator Klystron (SSUK) and its possible applications in the Particle Accelerator Physics, incoherent Self-Stimulated Undulator Radiation Sources (SSUR) and Free-Electron Lasers are discussed*.
* E.G.Bessonov et al., Self-Stimulated Undulator Radiation and its Possible Applications: http://arxiv.org/ftp/arxiv/papers/1009/1009.3724.pdf 		 
 
TUPO021 Dielectric Wakefield Accelerator to Drive the Future FEL Light Source wakefield, linac, electron, acceleration 1485
 
  • C.-J. Jing, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • J.G. Power, A. Zholents
    ANL, Argonne, USA
  
  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 ~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, ~1.2 kA of peak current, 1MHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered.  
 
TUPO035 Beam Dynamics at the ALICE Accelerator R&D Facility linac, simulation, booster, cavity 1512
 
  • F. Jackson
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Science and Technology Facilities Council
ALICE is an energy recovery accelerator which drives an infrared free electron laser (IR FEL), based at STFC Daresbury Laboratory. Beam dynamics are of primary importance for the operation of the IR FEL, to ensure sufficient peak current with minimal energy spread and transverse emittance. Measurements of beam parameters are presented and compared with particle tracking simulations. Of particular interest in the ALICE machine is the relatively long injection line where space charge and velocity bunching effects can be significant. 		 
 
TUPS008 The Gas Attenuator Vacuum System of FERMI@Elettra vacuum, photon, radiation, electron 1530
 
  • L. Rumiz, D. Cocco, C. Fava, S. Gerusina, R. Gobessi, E. Mazzucco, F. Zudini
    ELETTRA, Basovizza, Italy
  • M. Zangrando
    IOM-CNR, Trieste, Italy
  
  The FERMI@Elettra Free Electron Laser aims to produce a coherent light in the EUV-soft X-ray range employing High Gain Harmonic Generation (HGHG) schemes. The ultrafast, high intensity pulses are delivered to the experimental stations by means of a section called PADReS (Photon Analysis Delivery and Reduction System). Since several experiments need to reduce the FEL radiation intensity without changing the machine parameters, PADReS provides an integrated system to measure and reduce it up to 4 orders of magnitude. It is composed by a windowless gas-filled cell, a gas injection system, a differential pumping system, and the intensity monitors. The gas cell can be filled up to 0.15 mbar of nitrogen and the differential pumping system can keep up over 6 orders of magnitude. The pressure is finely regulated in the ·10-5 mbar range in the intensity monitor vacuum chamber, almost independently from the gas cell pressure level. The general layout and the performance of the differential pumping system prototype are presented.  
 
WEXA01 Challenges of 4th Generation Light Sources electron, emittance, undulator, photon 3798
 
  • C. Pellegrini
    SLAC, Menlo Park, California, USA
  • C. Pellegrini
    UCLA, Los Angeles, California, USA
  
  In the last few years Free Electron Lasers (FELs) have emerged as exceptionally exciting tools for new science. The results from FLASH (Hamburg) on biological imaging, LCLS (Stanford) which generated the first hard X-ray lasing and the projects proposed or in costruction around the world are rapidly moving the scientific community to the so called “fast science” which demands ultrashort pulses, fs synchronization, high brightness, high coherence X-rays. The basic SASE FEL process used so far converts energy jitter into jitter of the centralwavelength. Processes based on seeding and HGHG seem to offer a number of advantages in terms of bandwidth, coherence, stability and undulator length. This talk will present an overview of the 4th generation light sources, discussing the main challenges afforded in the construction of the operating facilities and considering the trends for the development of future facilities.  
slides icon Slides WEXA01 [10.640 MB]  
 
WEPC002 RF Separator and Septum Layout Concepts for Simultaneous Beams to RIB and FEL Users at ARIEL septum, linac, dipole, electron 1998
 
  • Y.-C. Chao, C. Gong, S.R. Koscielniak
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  
  A ½ MW capable CW electron linac is being designed and constructed at TRIUMF in support of the existing Rare Isotope Beam program. In the simplest configuration, the beam makes a single pass through three cryomodules to the RIB production targets. However, after the construction of a recirculation path, beam could make a second pass through two cryomodules with the RF phase advance adjusted to give energy recovery. Here it is proposed to time-interleave two bunch trains, and via an RF separator and septum, to direct one single-pass train to RIB production and the second train through the energy recovery ring that contains an IR FEL. It is also the intention, in single user mode, to use the ring as an energy doubler. This paper describes the RF separation scheme and options for the extraction optics that satisfy the requirements of “simultaneous” beams to two users.  
 
WEPO003 The FERMI@Elettra Magnets dipole, quadrupole, gun, electron 2409
 
  • D. Castronovo, R. Fabris, G.L. Loda, D. Zangrando
    ELETTRA, Basovizza, Italy
  
  FERMI@Elettra is a single-pass FEL user-facility located next to the third generation synchrotron radiation facility ELETTRA in Trieste, Italy. The linear accelerator contains more than 200 magnets. This paper reports on the design, construction, magnetic measurement and installation.  
 
THPC053 Shanghai Soft X-Ray Free Electron Laser Test Facility laser, radiation, linac, electron 3011
 
  • Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  
  As a critical development step towards constructing a hard X-ray FEL in China, a soft X-ray FEL test facility (SXFEL) was proposed and will be constructed at the SSRF campus by a joint team of Institute of Tsinghua University and Shanghai Institute of Applied Physics. This test facility, based on an 840MeV electron linear accelerator, aims at generating 9nm FEL radiation with two-stage cascaded HGHG scheme. The project proposal was approved in February 2011 by central government, and the constrction is expected to start in early 2012. This paper describes the preliminary design of this soft X-ray test facility and the R&D progress of the key FEL technologies in the SDUV-FEL test bench.  
 
THPC076 FEL Performance with Focusing Lattice Magnets Alignment Errors quadrupole, radiation, alignment, simulation 3071
 
  • V.G. Khachatryan, M. Ivanyan
    CANDLE, Yerevan, Armenia
  
  At the European XFEL the alignemnet errors of the undulator section quadrupole magnets will be corrected by applying beam based quadrupole alignment methods. Numerical simulations of the SASE process have been conducted to evaluate the FEL power reduction due to residual quadrupole alignment errors. FEL simulations with focusing lattice errors allow choosing an optimal error correction method in terms of FEL performance.  
 
THPC081 Status of the Free-Electron Laser FLASH at DESY undulator, photon, laser, radiation 3080
 
  • M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
    DESY, Hamburg, Germany
  
  The free-electron laser facility FLASH at DESY, Germany has been upgraded in 2010. Now, FLASH delivers an electron beam energy up to 1.25 GeV. The longitudinal phase-space is linearized by 3.9 GHz superconducting cavities. The facility delivers to users ultra-short laser like radiation pulses in the range of less than 50 fs to 200 fs in the soft X-ray wavelenth range from 44 down to 4.1 nm. FLASH provides hundreds to thousands pulses per second to users with unprecedented peak brilliance. FLASH will be upgraded with a second undulator beam line and an additional experimental hall. Construction starts Autumn 2011. We summarize the operational status of the ongoing 3rd user period.  
 
THPC082 Properties of the Radiation from the European X-ray Free Electron Laser electron, undulator, radiation, emittance 3083
 
  • E. Schneidmiller, M.V. Yurkov
    DESY, Hamburg, Germany
  
  Recent success of the Linac Coherent Light Source (LCLS) demonstrated feasibility for reliable production, compression, and acceleration of electron beams with emittances significantly smaller than original baseline parameters. The same scenario can be applied to the European XFEL as well. Experimental results from the Photo Injector Test Facility in Zeuthen (PITZ) demonstrated the possibility to generate electron beams with small charge and emittance. Computer modeling of the beam formation system also indicate on the possibility to preserve electron beam quality during acceleration and compression. Recently these trends have been analyzed, and baseline parameters of the European XFEL have been revised. Parameter space has been significantly extended in terms of the bunch charge. As a result, different modes of FEL operation become possible with essentially different properties of the radiation. In this paper we present an overview of radiation properties of SASE FEL radiators driven by electron beam with new baseline parameters.  
 
THPC083 Analysis of Parameter Space of a Kilowatt-scale Free Electron Laser for Extreme Ultraviolet Lithography Driven by L-band Superconducting Linear Accelerator Operating in a Burst Mode electron, radiation, undulator, laser 3086
 
  • E. Schneidmiller, V. Vogel, H. Weise, M.V. Yurkov
    DESY, Hamburg, Germany
  
  The driving engine of the Free Electron Laser in Hamburg (FLASH) is an L-band superconducting accelerator. It is designed to operate in a burst mode with 800 microsecond pulse duration at a repetition rate of 10 Hz. The maximum accelerated beam current during the macropulse is 10 mA. In this paper we analyze the parameter space for optimum operation of the FEL at the wavelength of 13.5 nm and 6.7 nm. Our analysis shows that the FLASH technology holds great potential for increasing the average power of the linear accelerator and an increase of the conversion efficiency of the electron kinetic energy to the light. Thus, it will be possible to construct a FLASH like free electron laser with an average power up to 3 kW. Such a source meets the requirements of the light source for the next generation lithography.  
 
THPC084 Optical Afterburner for a SASE FEL: First Results from FLASH electron, radiation, undulator, resonance 3089
 
  • M. Foerst
    CFEL, Hamburg, Germany
  • M. Gensch
    HZDR, Dresden, Germany
  • R. Riedel, E. Schneidmiller, N. Stojanovic, F. Tavella, M.V. Yurkov
    DESY, Hamburg, Germany
  
  Radiation Pulse from a Self-Amplified Spontaneous Emission Free Electron Laser (SASE FEL) consists out of spikes (wavepackets). Energy loss in the electron beam (averaged over radiation wavelength) also exhibits spiky behaviour on a typical scale of coherence length, and follows the radiation pulse envelope. These modulations of the electron beam energy are converted into large density (current) modulations on the same temporal scale with the help of a dispersion section, installed behind the x-ray undulator. Powerful optical radiation is then generated with the help of a dedicated radiator (afterburner). Envelope of the optical afterburner pulse is closely resembles the envelope of the x-ray pulse. We have recently demonstrated this principle at the Free Electron Laser in Hamburg (FLASH). We use THz undulator that is installed after the main X-ray as both dispersive element and radiator simultaneously. We characterize properties of the optical pulse using standard laser diagnostics techniques (i.e. FROG). Main result comes from the pulse duration measurement that we use to derive envelope of the x-ray radiation pulse duration which is in sub-100 fs range.  
 
THPC085 Effect of mirror-tilt on the mode-structure in an oscillator FEL coupling, cavity, simulation, alignment 3092
 
  • S. Krishnagopal, S.A. Samant
    BARC, Mumbai, India
  
  In an oscillator free-electron laser (FEL) the power coupled out depends strongly on the mode configuration at the out-coupling mirror. This mode configuration is affected by many parameters such as the resonator configuration, FEL wavelength, etc. In addition, mirror alignment also plays an important role in determining the mode structure. In this paper we use three-dimensional simulations (GENESIS+OPC), to study the effect of mirror tilt on the out-coupled power. We find that mirror-tilt can severely distort the mode, and can introduce non-Gaussian, non-axisymmetric modes. In this regard the confocal configuration is more robust compared to the concentric.  
 
THPC086 Status Report on FERMI@Elettra Project photon, linac, electron, undulator 3095
 
  • F. Parmigiani, M. Svandrlik, D. Zangrando
    ELETTRA, Basovizza, Italy
  
  Funding: This work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI@Elettra, a single-pass FEL user-facility covering the wavelength range from 100 nm (12 eV) to 3 nm (413 eV) located next to the third-generation synchrotron radiation facility Elettra in Trieste, Italy is actually under completion and will start user operation next year. The first seeded lasing was observed in December 2010 and the first experiments have started this year. In this paper an overview of the present status of machine and beamlines systems will be given as well as a status about operation and future upgrade. 		 
 
THPC087 Saturation Effect on VUV Coherent Harmonic Generation at UVSOR-II laser, electron, simulation, bunching 3098
 
  • T. Tanikawa, M. Adachi, M. Katoh, J. Yamazaki, H. Zen
    UVSOR, Okazaki, Japan
  • M. Hosaka, Y. Taira, N. Yamamoto
    Nagoya University, Nagoya, Japan
  
  Light source technologies based on laser seeding are under development at the UVSOR-II electron storage ring. In the past experiments, we have succeeded in generating coherent harmonics (CHs) in deep ultraviolet (UV) and vacuum UV (VUV) region and also in generating CH with variable polarizations in deep UV*. In previous conference, we reported an introduction of new-constructed spectrometer for VUV and results of spectra measurement, undulator gap dependence, and injection laser power dependence on VUV CHs**. This time we have successfully observed saturation on CHs intensities　and have found some interesting phenomena in different harmonic orders. In this conference, we will discuss the results of some systematic measurements and those analytical and particle tracking simulations***.
*M. Labat et al., Phys. Rev. Lett. 101 (2008) 164803.
**T. Tanikawa et al., Proc. IPAC'10, TUPE029, p. 2206 (2010).
***T. Tanikawa et al., Appl. Phys. Express 3 (2010) 122702. 		 
 
THPC096 Soft X-ray Free-electron Laser with a 10-time Reduced Size electron, undulator, bunching, laser 3113
 
  • Y.-C. Huang, F.H. Chao, C.H. Chen, K.Y. Huang
    NTHU, Hsinchu, Taiwan
  • P.J. Chou
    NSRRC, Hsinchu, Taiwan
  
  Funding: This work is supported by National Science Council under Contract NSC 99-2112-M-007 -013 -MY3.
We present a 30-m long soft x-ray FEL consisting of a 5-MeV photoinjector, a 150 MeV linac, a magnetic chicane compressor, and a 3-m long undulator. We employ both the 3rd and the 4th harmoincs of a Nd laser at 355 and 266 nm, respectively, to illuminate the cathode of the photoinjector. Owing to the beating of the two lasers, the emitted electron beam is modulated at 282 THz. The electrons are further accelerated to 150 MeV and, after acceleration, compressed by 33 times in a magnetic chicane. The temporal compression of the electron macropulse increases the electron bunching frequency to 9.3 PHz, corresponding to a soft x-ray wavelength of 32.2 nm. We adopt a solenoid-derived staggered array undulator* with a 3-m length, 5 mm undulator period, and 1.2 mm gap. With a solenoid field of 10 kG, we estimate an undulator parameter of 0.4 and a corresponding radiation wavelength of 32.2 nm for a 150 MeV driving beam. With 3.3-kA peak current, 0.03% energy spread, 2 mm-mrad emittance, and 80-micron beam radius at the undulator entrance, the GENESIS code predicts 0.2 GW radiation power from the 3-m long undulator for an initial bunching factor of merely 10 ppm.
* Y.C. Huang, H.C. Wang, R.H. Pantell, and J. Feinstein, "A staggered-array wiggler for far infrared, free-electron laser operation," IEEE J. Quantum Electronics 30 (1994) 1289. 		 
 
THPC097 Transverse Alignment Tolerances for the European XFEL Laser Heater laser, electron, undulator, emittance 3116
 
  • V.A. Goryashko
    NASU/IRE, Kharkov, Ukraine
  • M. Dohlus
    DESY, Hamburg, Germany
  • M. Hamberg, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  Funding: Supported by the KTH-SU-UU FEL Center.
We study the impact of misalignments between a laser beam and an electron bunch on the energy distribution function of the electron bunch in the laser heater. Transverse position and angular misalignment as well as different spot size of the laser and electron beam are considered. We find that the transverse misalignment makes the energy distribution function narrower compared to the case of ideal adjustment and a distinct peak in the distribution around the initial mean value of the energy appears. We demonstrate that despite these misalignments a uniform heating in terms of the energy spread can be achieved by appropriately adapting the transverse size and power of the laser beam such that the energy distribution function of the electron bunch at the end of the laser heater can be made similar to a Gaussian, thus providing more effective Landau damping against the micro-bunching instability. The laser power mainly determines the local energy spread while the laser spot size governs the shape of the energy distribution function. The transverse oscillations of electrons induced by the magnetic field in the laser heater are found to be non-essential for typical operation parameters. 		 
 
THPC100 Full Temporal Reconstruction using an Advanced Longitudinal Diagnostic at the SPARC FEL diagnostics, radiation, undulator, laser 3119
 
  • G. Marcus, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, V. Surrenti
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • A. Bacci, M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci, A.R. Rossi
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • V. Petrillo
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  
  The Production of ultra-short (sub 100 fs) single-spike radiation possessing full longitudinal coherence from a free-electron laser (FEL) has been the subject of intense study. A Frequency-Resolved Optical Gating (FROG) diagnostic has been developed and tested at UCLA, which has the capability of providing a longitudinal reconstruction of these ultra-fast pulses. This paper reports the results of the application of the diagnostic at the SPARC FEL facility.  
 
THPC101 Fitting Formulas for Space-charge Dominated Free-electron Lasers space-charge, electron, undulator, simulation 3122
 
  • G. Marcus, E. Hemsing, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  
  A simple power-fit formula for calculating the gain length of the fundamental Gaussian mode of a free-electron laser having strong space-charge effects in the 3D regime has been obtained. This tool allows for quick evaluation of the free-electron laser performance in the presence of diffraction, uncorrelated energy spread, and longitudinal space-charge effects. Here, we use it to evaluate the performance of high-gain FEL amplifiers considered candidates as high average power light sources. Results are compared with detailed numerical particle simulations using the free-electron laser code Genesis.  
 
THPC103 Beam Dynamics Study of X-band Linac Driven X-ray FELs linac, simulation, electron, optics 3128
 
  • Y. Sun, C. Adolphsen, C. Limborg-Deprey, T.O. Raubenheimer, J. Wu
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the DOE under Contract DE-AC02-76SF00515
Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. 		 
 
THPC104 Optimization for Single-Spike X-Ray Fels at LCLS with a Low Charge Beam undulator, laser, simulation, electron 3131
 
  • L. Wang, Y.T. Ding, Z. Huang
    SLAC, Menlo Park, California, USA
  
  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. At the low charge operation mode (20 pC), the x-ray pulse length can be <10 fs. In this paper we report our numerical optimization and simulations to produce even shorter x-ray pulses by optimizing the machine and undulator setup. In the soft x-ray regime, with the help of slotted-foil or undulator taper, a single spike x-ray pulse is achievable with peak FEL power of 30 GW.  
 
THPC105 An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source linac, ion, SRF, photon 3134
 
  • C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg
    JLAB, Newport News, Virginia, USA
  
  Funding: Support by US DoE contract #DE-AC05-060R23177.
We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ("afterburner"). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient. 		 
 
THPC106 Commissioning Status of the Fritz Haber Institute THz FEL electron, undulator, linac, gun 3137
 
  • A.M.M. Todd, H. Bluem, V. Christina, M.D. Cole, J. Ditta, D. Dowell, K. Jordan, R. Lange, J.H. Park, J. Rathke, T. Schultheiss, L.M. Young
    AES, Princeton, New Jersey, USA
  • W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W. Schöllkopf, G. von Helden
    FHI, Berlin, Germany
  • S.C. Gottschalk
    STI, Washington, USA
  
  The THz Free-Electron Laser (FEL) at the Fritz Haber Institute (FHI) of the Max Planck Society in Berlin is designed to deliver radiation from 3 to 300 microns using a single-plane-focusing mid-IR undulator and a two-plane-focusing far-IR undulator that acts as a waveguide for the optical mode. A key aspect of the accelerator performance is the low longitudinal emittance, < 50 keV-psec, that is specified to be delivered at 200 pC bunch charge and 50 MeV from a gridded thermionic electron source. We utilize twin accelerating structures separated by a chicane to deliver the required performance over the < 20 - 50 MeV energy range. The first structure operates at near fixed field while the second structure controls the output energy, which, under some conditions, requires running in a decelerating mode. "First Light" is targeted for the centennial of the sponsor in October 2011 and we will describe progress in the commissioning of this device to achieve this goal. Specifically, the measured performance of the accelerated electron beam will be compared to design simulations and the observed matching of the beam to the mid-IR wiggler will be described.  
 
THPC142 Burst Pulse Superimposed Electron Beam Acceleration in LEBRA FEL Linac electron, acceleration, linac, gun 3218
 
  • T. Tanaka, K. Hayakawa, Y. Hayakawa, M. Inagaki, K. Nakao, K. Nogami, N. Sato
    LEBRA, Funabashi, Japan
  • S. Aizawa, Y. Arisumi, K. Shinohara
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  • I. Sato
    Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan
  
  The electron beam for free electron laser (FEL) at the Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University had been extracted from a conventional DC triode electron gun system. In conjunction with the renewal of the gun high voltage terminal a Kentech high-speed grid pulser was installed in addition to the conventional grid pulser. The 89.25MHz sine wave frequency-divided from the 2856MHz accelerating RF has been applied to the high-speed grid pulser, generating 64 or 128 frequency-divided grid pulses synchronous with the round-trip time in the FEL optical resonator. The high-speed grid pulses have been applied to the EIMAC Y646B cathode simultaneously with the conventional macropulse through the pulse coupling strip-line circuit; the resultant beam has been the short pulse beam superimposed on the macropulse beam. By reducing the macropulse voltage, only the train of the burst beam with 0.6ns width has been extracted. The peak burst beam current roughly 6 times higher than the conventional macropulse beam has been obtained with the Farady cup at the end of the FEL beamline. The FEL lasing experiment with the burst beam is underway.  
 
THPC164 Phase Shifters for the FERMI@Elettra Undulators undulator, electron, radiation, polarization 3278
 
  • B. Diviacco, R. Bracco, D. Millo, M.M. Musardo
    ELETTRA, Basovizza, Italy
  
  The variable gap undulator system in operation at the FERMI@Elettra Free Electron Laser facility requires adjustable phase matching devices between consecutive radiator segments in order to maintain optimal lasing conditions while changing the radiation properties. A permanent magnet phase shifter has been designed to achieve the required electron beam delay in a compact structure that could be installed in close proximity to the undulators. In this paper we present the design of the phasing units and the results of the magnetic measurements performed on the five devices installed so far. We also describe the method used to properly set their field strength for any given electron energy, radiation wavelength and polarization.  
 
THPC170 Magnetic Characterization of FEL-2 Undulators for the FERMI@Elettra Free-electron Laser undulator, multipole, sextupole, quadrupole 3296
 
  • M. Kokole
    KYTE, Sezana, Slovenia
  • B. Diviacco
    ELETTRA, Basovizza, Italy
  • T. Milharcic, M. Zambelli
    KYMA, Trieste, Italy
  • G. Soregaroli, M. Tedeschi
    Euromisure srl, Pieve S. Giacomo (Cremona), Italy
  
  Kyma Srl is the spin-off company of Sincrotrone Trieste, Elettra laboratory, set up in 2007 together with the two industrial partners Cosylab d.d. and Euromisure SpA, in order to design and manufacture the undulators for the FERMI@Elettra project in Trieste, Italy. The insertion devices, for FEL-2 line, manufactured and characterized so far are the following: Modulator, 3.2 m linearly polarized undulator, three 55.2 mm APPLE-II variable polarization undulators, each 2.4 m long and six 34.8 mm APPLE-II undulators also each 2.4 m long. All the above devices have been characterized, both from the mechanical and the magnetic point of view. The measured parameters are in good agreement with the design values. This paper presents the most relevant changes in design from FEL-1 to FEL-2 line and results of the magnetic measurements carried out on all the above undulators.  
 
THPC183 Application of the Balanced Hybrid Mode in Overmoded Corrugated Waveguides to Short Wavelength Dynamic Undulators undulator, cavity, impedance, electron 3326
 
  • S.G. Tantawi, G.B. Bowden, C. Chang, J. Neilson, M. Shumail
    SLAC, Menlo Park, California, USA
  • C. Pellegrini
    UCLA, Los Angeles, California, USA
  
  Funding: Work Supported by the US Department of Energy
Inspired by recent developments in low-loss overmoded components and systems for ultra-high power RF systems, we explored several overmoded waveguide systems that could function as RF undulators. One promising structure is a corrugated waveguide system operating at the hybrid HE11 mode. This is a new application for that mode. Initial calculations indicate that such a system can be operated at relatively low power levels while obtaining large values for the undulator parameters. RF surface fields are typically low enough to permit superconducting operation. This technology could realize an undulator with short wavelengths and also dynamic control of the undulator parameters including polarization. We introduce the scaling laws governing such a structures, and then show with exact simulations an undulator design that have a wavelength of about 1.4 cm with an undulator parameter K~1. This undulator is intended to be powered by a 50 MW source at a frequency of 11.4 GHz. We describe the experimental setup for testing such a technology. 		 
 
THPS009 Coherent Electron Cooling Demonstration Experiment electron, ion, hadron, wiggler 3442
 
  • V. Litvinenko, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A.V. Fedotov, Y. Hao, D. Kayran, G.J. Mahler, W. Meng, T. Rao, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  • G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
    Tech-X, Boulder, Colorado, USA
  • A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
    JLAB, Newport News, Virginia, USA
  • M.A. Kholopov, P. Vobly
    BINP SB RAS, Novosibirsk, Russia
  
  Coherent electron cooling (CEC) is considered to be on of potential candidates capable of cooling high-energy, high-intensity hadron beams to very small emittances. It also has a potential to significantly boost luminosity of high-energy hadron-hadron and electron-hadron colliders. In a CEC system, a perturbation of the electron density caused by a hadron is amplified and fed back to the hadrons to reduce the energy spread and the emittance of the beam. Following the funding decision by DoE office of Nuclear Physics, we are designing and building coherent electron cooler for a proof-of-principle experiment at RHIC to cool 40 GeV heavy ion beam. In this paper, we describe the layout of the CeC installed into IP2 interaction region at RHIC. We present the design of the CeC cooler and results of preliminary simulations.