Keyword: FEL
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MOYCB101 Brightness and Coherence of Synchrotron Radiation and FELs radiation, brightness, electron, undulator 16
 
  • Z. Huang
    SLAC, Menlo Park, California, USA
  
  Essential properties of radiation from storage rings and FELs include spatial- and temporal beam brightness and coherence. Starting from a fundamental representation of the electron beam as a radiating source the electromagnetic power can be represented as modes in phase-space to characterize beam quality. For storage rings, conditions for transverse coherence are possible which can lead to high-resolution imaging under a variety of polarization conditions. For FELs the radiation brightness is over 10 orders of magnitude higher with finite temporal coherence times and much of the total FEL power contained in the dominant mode. This presentation should provide an overview of the above.  
slides icon Slides MOYCB101 [9.731 MB]  
 
MOPEA077 Accelerator Physics and Light Source Research Program at Duke University wiggler, storage-ring, electron, feedback 264
 
  • Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  
  Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
he accelerator physics and light source research program at Duke Free-Electron Laser Laboratory (DFELL), TUNL, is focused on the development of the storage ring based free-electron lasers (FELs), and a state-of-the-art Compton gamma-ray source, the High Intensity Gamma-ray Source (HIGS). Driven by the storage ring FEL, the HIGS is world's most intense Compton gamma-ray source with a maximum total flux of few 1010 gamma per second (around 10 MeV). Operated in the energy range from 1 to 100 MeV, the HIGS is a premier nuclear physics research facility in the world. In 2012, we completed a major accelerator upgrade project with a wiggler switchyard system which allows the configuration changes between planar and helical FEL wigglers, and a great enhancement of the FEL gain when operated with 3 or 4 helical wigglers. In this paper, we will describe our ongoing light source development to produce gamma-ray beams in the new energy range of 100 and 158 MeV. We will also provide a summary of our accelerator physics research activities in the area of nonlinear dynamics, beam instability research, and FEL research. 		 
 
MOPEA078 Commissioning and Operation of Wiggler Switchyard System for Duke FEL and HIGS wiggler, vacuum, storage-ring, lattice 267
 
  • Y.K. Wu, M.D. Busch, M. Emamian, J.F. Faircloth, H. Hao, J.Y. Li, S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, P. Wang, J. Yan
    FEL/Duke University, Durham, North Carolina, USA
  • A.L. Wu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
To enable the Duke storage ring FEL to operate in VUV with adequate gain, a major storage ring upgrade was carried out in 2012 to install two additional helical FEL wigglers with a wiggler switchyard system. Using the switchyard, a quick changeover can be made between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight section. This system preserves the linear polarization capabilities of the Duke FEL and gamma-ray beams at the High Intensity Gamma-ray Source (HIGS), while enabling VUV FEL operation with a higher gain using a longer FEL with as many as four helical wigglers. The wiggler switchyard upgrade was completed in Summer 2012, followed by a rapid and successful commissioning of the Duke storage ring, FEL system, and HIGS. In this paper, we will present the results of accelerator and light source commissioning with the wiggler switchyard. We will also present preliminary results of operating the OK-5 FEL in different configurations. With the wiggler switchyard, we are well positioned to realize the operation of a VUV FEL below 190 nm and production of Compton gamma-ray beams above 100 MeV in circular polarization. 		 
 
MOPEA083 Energy Modulation in Coherent Electron Cooling electron, ion, plasma, simulation 276
 
  • G. Wang, M. Blaskiewicz, V. Litvinenko
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron cooling (CeC) relies on Debye shielding to imprint information of the ion beam to an electron beam [1]. Apart from the density modulation, Debye shielding also modulates the energy of electrons, which provides additional seeding for the free electron laser (FEL) amplifier. In this work, we show that the energy modulation of a longitudinal slice of the electrons, induced by dynamic Debye shielding of a moving ion in anisotropic electron plasma with κ-2 velocity distribution, can be expressed into a 1D integral. The results are then applied to the 1D FEL model to investigate the effects of energy modulation to the correcting force in the kicker.
[1] V.N. Litvinenko, Y.S. Derbenev, Coherent Electron Cooling, Physical Review Letters, 102 (2009) 114801. http://link.aps.org/abstract/PRL/v102/e114801 		 
 
MOPFI020 Cold Test of the Coaxial Cavity for Thermionic Triode Type RF Gun cavity, gun, resonance, electron 324
 
  • T. Konstantin, Y.W. Choi, T. Kii, R. Kinjo, K. Masuda, M. Mishima, K. Nagasaki, H. Negm, H. Ohgaki, K. Okumura, M. Omer, S. Shibata, K. Shimahashi, K. Yoshida, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  A thermionic rf gun has several advantages as compared to photocathode gun. Such as low cost, high averaged current and simple operation. However a thermionic rf gun has a significant disadvantage in form of back bombardment effect. The KU-FEL facility is an oscillator type FEL, which uses a thermionic 4.5 cell S-band RF gun for electron beam generation. The back bombardment effect causes increasing current in macropulse, which limits the gain of the FEL. In order to mitigate the current increase we plan to modify thermionic rf gun to triode type rf gun. Therefore an additional rf cavity has been designed. This cavity has separate rf power supply with amplitude and phase control. By this means we can properly adjust the injection of electrons into the main gun body. According to simulations the triode type gun can reduce 80% of back streaming electron energy*. The cold tests of the first prototype have revealed deviation from designed values**. Based on the tests of the first prototype new prototype with integrated mechanism for resonance tuning has been designed and fabricated. In this work we report the cold test of the redesigned prototype of the coaxial rf cavity.
* K. Masuda et al. Proceedings of FEL 2006, BESSY Berlin.
** M. Takasaki et al. Proceedings of FEL 2010, Malbö
 		 
 
MOPFI036 Study of the Cold Cathode RF Electron Gun Based on Doped Diamond Films at CAEP gun, cathode, electron, emittance 366
 
  • X. Li
    TUB, Beijing, People's Republic of China
  • W. Bai, M. Li
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  Diamond relevant materials have been considered as a promising field emission cathode in recent years. High current density can be obtained either by diamond field emission arrays or by doped diamond films under electrical strengths of several decades of MV/m. Based on the doped films a half cell S-band electron gun has been designed and constructed at CAEP. The gun can provide an accelerating gradient of 60-80 MV/m on the cathode surface (6 mm in diameter). Simulations have proven good performance of such a gun but it needs confirmed by further experiments. Details of the experiments and comparisons with simulations will be reported.  
 
MOPFI044 VHF Gun Research at SINAP gun, cavity, electron, vacuum 380
 
  • Q. Gu, L. Chen, W. Fang, G.Q. Lin
    SINAP, Shanghai, People's Republic of China
  
  The R&D work on the high power THz based on energy recovery linac (ERL) has been carried out in Shanghai Institute of Applied Physics (SINAP). One of the key components for the ERL is the high brightness electron source. The low frequency gun technology has been adopted, by comparing with the SRF gun and DC gun. In this paper, the design and cold test of a 250MHz gun will be presented.  
 
MOPME005 Goubau Line and Beam Characterization of TURBO-ICT for SwissFEL instrumentation, resonance, electron, laser 476
 
  • S. Artinian, J.F. Bergoz, F. Stulle
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • P. Pollet, V. Schlott
    PSI, Villigen PSI, Switzerland
  
  SwissFEL will be able to operate with electron bunch doublets 28ns apart. Each of the bunches carries 10pC to 200pC of charge with bunch lengths of a few femto-seconds. For charge calibration of the FEL photon pulses, a measurement accuracy of 1% is desired. The Turbo-ICT accomplishes these requirements with negligible beam position and bunch length dependence. It is insensitive to dark current and features high immunity to background noise. We characterize the Turbo-ICT performance on a Goubau line, also known as single-wire transmission line. The Goubau line utilizes electromagnetic fields with frequencies up to many GHz. It allows accurate bench testing including beam position and bunch length dependence. The results are compared to beam measurements performed at the SwissFEL Injector Test Facility (SITF).  
 
MOPME036 Prototype Experiment Preparation of a 54.167MHz Laser Wire System for FEL-THz Facility at CAEP laser, electron, photon, cathode 550
 
  • D. Wu
    TUB, Beijing, People's Republic of China
  • W. Bai, M. Li, H. Wang, J. Wang, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  In this paper, a prototype experiment preparation of a 54.167 MHz laser wire system is presented, which will be used to measure the beam size of a CW DC gun built as an electron source of FEL-THz facility in China Academmy of Engineering Physics (CAEP). The rms beam size is less than 1 mm and the average current of the electron beam is more than 1 mA. This new-type LW system ultilizes the excess power other the photocathode drive laser and becomes much cheaper and simpler. Plus, it can distinguish beams with different energies which are very close in ERLs. The system layout and the simulation results are also presented.  
 
MOPME051 Development of Cavity Beam Position Monitor System cavity, simulation, coupling, electron 586
 
  • B.P. Wang, Y.B. Leng, Y.B. Yan, L.Y. Yu, R.X. Yuan, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  
  Shanghai soft X-ray free electron laser (SXFEL) facility requires beam position resolution better than 1 μm in the undulator sections. Cavity BPM system, feasible in obtaining sub micron position resolution, has been developed to achieve the goal. Two cavity prototypes with high Q and low Q were designed and fabricated. The relevant dedicated electronic, which could cover the two types of cavity BPMs, also have been developed. Fast fourier transform (FFT) and digital down converted based algorithms were implemented. The beam test of the whole system has been scheduled on the Shanghai deep ultraviolet (SDUV) FEL facility. The cavity design, electronic architecture, achieved performance during beam test will be presented.  
 
MOPME067 Non-Invasive Bunch Length Diagnostics Based on Interferometry From Double Diffraction Radiation Target target, radiation, electron, diagnostics 631
 
  • D.A. Shkitov, G.A. Naumenko, A. Potylitsyn, M.V. Shevelev
    TPU, Tomsk, Russia
  • H.X. Deng, S.L. Lu, T. Yu, J.B. Zhang
    SINAP, Shanghai, People's Republic of China
  
  Funding: This work was supported by the joint Russian-Chinese grant (RFBR 110291177 and NSFC 11111120065) and partially by the Program of Russian MES “Nauka” and the SINAP Xinrui Program Y15501A061.
Reliable and precise non-invasive beam diagnostics technique to measure length of sub-picosecond electron bunches are required for new accelerator facilities (FEL, et al.). Investigations of coherent radiation generated by such bunches using different interferometers allow to determine a bunch length*. Measuring a dependence of radiation yield intensity from two DR targets on a distance between them (the intrinsic DR interferogram), it is possible to obtain the same information. Such a non-invasive technique can be directly used for ultra-short bunch length measurements. Recently the first experiment with a double DR target was carried out at the SINAP fs linac facility** with parameters described in***. The double DR target was consisted of two plates made from Al foil. The pyro-electric detector SPI-D-62 was used. Here we report the results of the second stage of our investigations. The DR interferograms of different electron bunch length were measured. The bunch length was reconstructed using the heuristic model based on the dimension theory and simulation data. We compare the results from DR interferograms and Michelson interferometer measurements and show their similarity.
*Murokh A. et al., NIMA 410 (1998) 452.
**Zhang J.B., Shkitov D.A. et al., IBIC’12 MOPB65 (2012).
***Lin X., Zhang J. et al., Chin. Phys. Let. V. 27 N. 4 (2010) 044101. 		 
 
MOPWA050 Bunch Train Characterisation for an Infra-red FEL Driven by an Energy Recovery Linac electron, pick-up, EPICS, diagnostics 786
 
  • T.T. Thakker, D. Angal-Kalinin, D.J. Dunning, F. Jackson, S.P. Jamison, J.K. Jones, N. Thompson
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The IR-FEL on the ALICE test facility in the UK first achieved lasing in October 2010 and has since been characterised in terms of its output *. In this work we make a characterisation of electron bunch properties along a complete 100us macropulse to characterise the lasing-induced energy change and its effect on energy recovery. Measurements of bunch energy and timing are correlated with the FEL radiation output and discussed.
* N. R. Thompson et al, ‘First lasing of the ALICE infra-red Free-Electron Laser’, Nuclear Instruments and Methods A, 680 (2012) 117–123 		 
 
MOPWA069 Time-resolved Electron Beam Position Monitor Macropulse Waveform Measurement in MkV Linear Accelerator at University of Hawaii Free Electron Laser Laboratory electron, controls, free-electron-laser, laser 837
 
  • P. Niknejadi, M.R. Hadmack, B.T. Jacobson, J. Madey, G.S. Varner
    University of Hawaii, Honolulu, HI, USA
  
  Real time waveform measurements of electron beams will provide valuable data and possibility of online bunch diagnostics in linear accelerators. The University of Hawaii Linear Accelerator utilizes a thermionic LaB6 cathode microwave gun injector and a single section of S-band linear accelerator capable of producing a 40MeV, 1-2 ps bunched electron beam with average current of 200mA over the duration of a 4.5 us macropulse. This beam, pulsed at 4 Hz, produces strong RF signal at 2.856 GHz which is coupled out of the beam-pipe by a family of stripline beam position monitors (BPM's) and read out using custom built logarithmic-difference based electronics installed in 2012.* A high speed Analog to Digital Convertor and Field-Programmable Gate Array will be used to digitize the signal and record the waveform. The goal is to make a cost effective oscilloscope on a chip/board with feasible and functional operation to achieve optimal beam configuration. The circuit board design, in-circuit programming, waveform digitization challenges, and preliminary results from the prototype will be presented at the conference.
* B. T. Jacobson, M. R. Hadmack, J. M. J. Madey, P. Niknejadi "Modular Logarithmic Amplifier Beam Position Monitor Readout System at University of Hawai’i," IBIC Conf. Proc. (2012)
 		 
 
MOPWO071 Coherent Electron Cooling: Status of Single-Pass Simulations electron, simulation, ion, bunching 1049
 
  • B.T. Schwartz, G.I. Bell, I.V. Pogorelov, S.D. Webb
    Tech-X, Boulder, Colorado, USA
  • D.L. Bruhwiler
    CIPS, Boulder, Colorado, USA
  • Y. Hao, V. Litvinenko, G. Wang
    BNL, Upton, Long Island, New York, USA
  • S. Reiche
    PSI, Villigen PSI, Switzerland
  
  Funding: US DOE Office of Science. Contracts DE-FC02-07ER41499, DE-FG02-08ER85182, DE-AC02-05CH11231.
Advances in nuclear physics depend on experiments that employ relativistic hadron accelerators with dramatically increased luminosity. Current methods of increasing hadron beam luminosity include stochastic cooling and electron cooling; however, these approaches face serious difficulties at the high intensities and high energies proposed for eRHIC *. Coherent electron cooling promises to cool hadron beams at a much faster rate**. A single pass of an ion through a coherent electron cooler involves the ion's modulating the charge density of a copropagating electron beam, amplification of the modulated electron beam in a free-electron laser, and energy correction of the ion in the kicker section. Numerical simulations of these three components are underway, using the parallel Vorpal framework and Genesis 1.3, with careful coupling between the two codes. Here we present validations of two components of the simulations: Adding bunching to an electron beam at the start of an FEL, and the time-dependent charge density modulation in the kicker.
* http://www.bnl.gov/cad/eRHIC/
** V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009). 		 
 
MOPWO078 A Harmonic Kicker Scheme for the Circulator Cooler Ring in the Medium Energy Electron-ion Collider kicker, electron, ion, collider 1061
 
  • E.W. Nissen, A. Hutton, A.J. Kimber
    JLAB, Newport News, Virginia, USA
  
  Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The current electron cooler design for the proposed Medium Energy Electron-Ion collider (MEIC) at Jefferson Lab utilizes a circulator ring for reuse of the cooling electron bunch up to 100 times to cool the ion beams. This cooler requires a fast kicker system for injecting and extracting individual bunches in the circulator ring. Such a kicker must work at a high repetition rate, up to 7.5 to 75 MHz depending on the number of turns in the recirculator ring. It also must have a very short rise and fall time (of order of 1 ns) such that it will kick an individual bunch without disturbing the others in the ring. Both requirements are orders of magnitude beyond the present state-of-the-art as well as the goals of other on-going kicker R&D programs such as that for the ILC damping rings. In this paper we report a scheme of creating this fast, high repetition rate kicker by combining RF waveforms at multiple frequencies to create a kicker waveform that will, for example, kick every eleventh bunch while leaving the other ten unperturbed. We also present a possible implementation of this scheme as well as discuss its limitations. 		 
 
TUOCB102 SPARC_LAB Recent Results laser, electron, plasma, photon 1114
 
  • M. Ferrario, D. Alesini, M.P. Anania, A. Bacci, M. Bellaveglia, M. Castellano, E. Chiadroni, D. Di Giovenale, G. Di Pirro, A. Drago, A. Esposito, A. Gallo, G. Gatti, A. Ghigo, T. Levato, A. Mostacci, L. Palumbo, A.R. Rossi, B. Spataro, C. Vaccarezza, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • G. Dattoli, E. Di Palma, L. Giannessi, A. Petralia, C. Ronsivalle, V. Surrenti
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • C. De Martinis
    INFN/LASA, Segrate (MI), Italy
  • R. Faccini
    INFN-Roma, Roma, Italy
  • M. Gambaccini
    INFN-Ferrara, Ferrara, Italy
  • D. Giulietti
    UNIPI, Pisa, Italy
  • L.A. Gizzi, L. Labate
    CNR/IPP, Pisa, Italy
  • S. Lupi
    Università di Roma I La Sapienza, Roma, Italy
  • V. Petrillo, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  • G. Turchetti
    Bologna University, Bologna, Italy
  
  A new facility named SPARC_LAB (Sources for Plasma Accelerators and Radiation Compton with Lasers and Beams) has been recently launched at the INFN National Labs in Frascati, merging the potentialities of the an ultra-brilliant electron beam photoinjector and of a high power Ti:Sa laser. The test facility is now completed, hosting a 150 MeV high brightness electron beam injector which feeds a 12 meters long undulator. Observation of FEL radiation in variuous configurations has been performed. In parallel to that a 200 TW laser that is linked to the linac and devoted to explore laser-matter interaction, in particular with regard to laser-plasma acceleration of electrons (and protons) in the self injection and external injection modes. The facility will be also used for particle driven plasma acceleration experiments (the COMB experiment). A Thomson scattering experiment coupling the electron bunch to the high-power laser to generate coherent monochromatic X-ray radiation is also in the commissioning phase. We report in this paper the recent results obtained at the SPARC_LAB facility.  
slides icon Slides TUOCB102 [12.874 MB]  
 
TUPEA004 The Free-electron Laser FLASH at DESY photon, gun, linac, undulator 1167
 
  • M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
    DESY, Hamburg, Germany
  
  The free-electron laser FLASH at DESY routinely produces up to several thousand photon pulses per second with wavelengths ranging from 44 nm down to as low as 4.25 nm and with pulse energies of up to 400μJoule. After a significant technical upgrade in 2010, which included an energy upgrade to 1.25 GeV and linearization of the longitudinal phase space by 3-rd harmonic cavities, emphasis was put on consolidation and automatization of operational procedures and better control of the electron/photon beam properties. Some highlights are: on-line measurements of the electron bunch-length in the regime of several 10 fs to 100 fs, reaching into the water window, increased photon pulse energies and the improved machine reproducibility. Moreover, first evidence of HHG seeding was found at the sFLASH experiment in spring 2012. Construction work is ongoing for a 2-nd beam-line (FLASH-2) for which commissioning will start in late 2013.  
 
TUPEA006 Towards Realistic Modelling of the FEL Radiation for the European XFEL simulation, radiation, controls, undulator 1173
 
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  
  For the operation phase of the European XFEL the possibility to characterize the FEL radiation taking realistic machine model into account is important. To achieve this, a software framework is being developed. It allows for interoperability of various simulation codes by means of a common graphical user interfaces, common input and output files, and common programming model for scripting; it includes the possibility of modeling beam jitters and machine imperfections to set errorbars on the simulation results, and has a connection to the control system for data acquisition. We report on the progress in the developing of this framework and give examples of FEL property calculations performed with it.  
 
TUPEA007 Spontaneous Radiation Calculations for the European XFEL undulator, radiation, electron, emittance 1176
 
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  • O.V. Chubar
    BNL, Upton, Long Island, New York, USA
  • M. Scheer, M. Titze
    HZB, Berlin, Germany
  • N.V. Smolyakov, S.I. Tomin
    NRC, Moscow, Russia
  
  Calculating spontaneous radiation emission from long undulators such as those present in the European XFEL, being background to FEL radiation, is still important for several diagnostics and science cases. For realistic setups, and including effects of electron beam focusing, emittance and energy spread in the electron beam, these calculations should be performed numerically. We present these calculations for several electron beam and undulator parameters performed by various codes. Sensitivity of different spontaneous radiation characteristics, in various collection schemes, to the electron beam and undulator magnetic field parameters is studied  
 
TUPEA010 FERMI Seeded FEL Progress Report laser, electron, undulator, free-electron-laser 1182
 
  • M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, M. Kiskinova, G.L. Loda, M. Lonza, B. Mahieu, N. Mahne, C. Masciovecchio, F. Parmigiani, G. Penco, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, L. Sturari, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  • B. Mahieu
    CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
  
  Funding: Work supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI, the seeded Free Electron Laser located at the Elettra laboratory in Trieste, Italy, welcomed in December 2012 the first external users on the FEL-1 line. This line is based on a single stage of High Gain Harmonic Generation (HGHG), seeded by a UV laser, and covers wavelengths between 80 and 20 nm. The photon energy reached more than 300 μJ. The second FEL line, FEL-2, covering the lower wavelength range between 20 and 4 nm thanks to a double stage cascaded HGHG scheme, has generated its first coherent photons in October 2012. This is the first experimental demonstration of a seeded free electron laser configured as a two stages cascade operating in the "fresh bunch injection” mode, where the second stage is seeded by the light produced by the first stage. This paper describes the status of the operation and user experiments with FEL-1 and reports about the progress in the commissioning of FEL-2. 		 
 
TUPEA011 Double Stage Seeded FEL with Fresh Bunch Injection Technique at FERMI@Elettra laser, electron, undulator, photon 1185
 
  • S. Di Mitri, E. Allaria, D. Castronovo, P. Cinquegrana, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, A.A. Demidovich, B. Diviacco, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, G. Gaio, L. Giannessi, R. Ivanov, B. Mahieu, N. Mahne, I. Nikolov, F. Parmigiani, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  
  During the month of October 2012 the commissioning of the light source FEL-2 at FERMI was successfully concluded. Fermi FEL-2 is the first seeded FEL operating with a double stage cascade in the "fresh bunch injection" mode*. The two stages are two high gain harmonic generation FELs where the first stage is seeded by the 3rd harmonic of a Ti:Sa laser system, which is up converted to the 4th-12th harmonic. The output of the first stage is then used to seed the second stage. A final wavelength of 10.8 nm was obtained as the 24th harmonic of the seed wavelength at the end of the two frequency conversion processes, demonstrating that the FEL is capable of producing single mode narrow bandwidth pulses with an energy of several tens ofμjoules. We report on the experimental characterisation of the FEL performances in this configuration.
* I. Ben-Zvi, K. M. Yang, L. H. Yu, ”The ”fresh-bunch” technique in FELs”, NIM A 318 (1992), p 726-729 		 
 
TUPEA013 Present Status of Mid-infrared Free Electron Laser Facility in Kyoto University gun, electron, undulator, cavity 1190
 
  • H. Zen, Y.W. Choi, H. Imon, M. Inukai, T. Kii, R. Kinjo, T. Konstantin, K. Masuda, K. Mishima, H. Negm, H. Ohgaki, K. Okumura, M. Omer, S. Shibata, K. Shimahashi, K. Yoshida
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  A Mid-Infrared Free Electron Laser (MIR-FEL) facility named as KU-FEL has been constructed for energy science in Institute of Advanced Energy, Kyoto University*. The accelerator of KU-FEL consists of an S-band 4.5-cell thermionic RF gun, a Dog-leg section for energy filtering, a 3-m traveling-wave type accelerator tube, 180-degree arc section for bunch compression and a hybrid undulator. We have already succeeded in lasing of the FEL from 5.5 to 14.5 micro-meter. Present status and recent activity for the FEL development will be presented in the conference.
*H. Zen, et al., Infrared Physics & Technology, vol.51, 382-385. 		 
 
TUPEA028 Echo-enabled Harmonic Generation based on Hefei Storage Ring electron, bunching, laser, storage-ring 1208
 
  • H.T. Li, W.W. Gao, Q.K. Jia, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Echo-Enabled Harmonic Generation (EEHG) has been proposed and experimently demonstrated recently. In this paper, we numerically investigate the possibility of operating EEHG based on Hefei storage ring, which has a short circumference and a small momentum compaction factor. The difference to other similar reserch is that we use the whole ring as the first dispersive section and an optical klystron as the second one.  
 
TUPEA030 High Brightness and Fully Coherent X-ray Pulses from XFELO Seeded High-gain FEL Schemes radiation, electron, cavity, undulator 1214
 
  • H.X. Deng, C. Feng
    SINAP, Shanghai, People's Republic of China
  
  The successful operation of the hard x-ray self-seeding experiment at the LCLS opens the era of fully coherent hard x-ray free electron lasers (FELs). However, the shot-to-shot radiation fluctuation is still a serious issue. In this paper, high-gain, single-pass x-ray FEL schemes seeded by the narrow bandwidth radiation signal from an x-ray FEL oscillator were proposed and investigated, which are expected to generate high brightness, fully coherent and stable x-ray pulse. A simple model has been developed to figure out the temporal and the spectral structures of the output pulses in x-ray FEL oscillator. And options using two synchronized accelerators and using one accelerator were considered, respectively.  
 
TUPEA033 Proposals for Chirped Pulse Amplification in HGHG and CHG at SDUV-FEL laser, electron, radiation, undulator 1217
 
  • C. Feng, L. Shen, D. Wang, D. Xiang, M. Zhang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  
  In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of the SDUV-FEL.  
 
TUPEA042 Linac Design for Dalian Coherent Light Source linac, emittance, simulation, laser 1226
 
  • M. Zhang, H.X. Deng, D. Gu, Q. Gu
    SINAP, Shanghai, People's Republic of China
  
  Dalian Coherent Light (DCL) Source is a FEL user facility in which HGHG scheme is adopted. Beam quality requirements for the linear accelerator (linac) are critical, including not only the beam brightness, but also the stability and the reliability. In this paper, optimization study is performed for the linac. Based on beam stability simulation in the longitudinal direction, the tolerant budget is formed for the short period jitter. For the transverse orbit error, beam based alignment (BBA) technique is implemented by beam dynamics simulations and the transverse jitter is also presented accordingly. Measurement method for the beam quality is also described in the paper.  
 
TUPEA044 The Design of Control System for the Optical Cavity Adjuster of a FEL-THz Source controls, cavity, electron, undulator 1232
 
  • X. Liu, Q. Fu, B. Qin, P. Tan, C. Wang, Y.Q. Xiong, J. Yang, H. Zeng
    HUST, Wuhan, People's Republic of China
  
  The optical cavity adjuster is an important sub-system in a FEL-THz source, which is used to adjust the position and angle of the optical cavity with a high precision. In view of the requirements of the optical cavity adjuster of the FEL-THz source, this paper presents the design of the control system of the optical cavity adjuster. The design of the control system based on a PC and a motion controller is adopted. The motion controller controls high-precision linear stage to adjust linear direction and picomotors are controlled to enable the adjustment of roll and yaw. According to relevant calculation, the range of linear direction and the accuracy can be reached at ±3mm and 0.2~0.5μm; the range of the adjustment of roll and yaw and the accuracy can be reached at ±2° and 20″. In summing up it can be stated that the design meets the requirements and it also lays the foundation for engineering on developing the optical cavity adjuster.  
 
TUPEA050 Extension of the MAX IV Linac for a Free Electron Laser in the X-ray Region linac, undulator, emittance, electron 1244
 
  • F. Curbis, N. Čutić, M. Eriksson, O. Karlberg, F. Lindau, A. Mak, E. Mansten, S. Thorin, S. Werin
    MAX-lab, Lund, Sweden
  
  The 3 GeV linac for the MAX IV laboratory is currently under construction in Lund (Sweden). As full energy injector for the MAX IV rings, a thermionic gun will be used to create electrons. However a photocathode gun planned for a short pulse facility (SPF) will deliver small emittance and ultra-short electron bunches that will be suitable to also drive a Free-Electron Laser. Moreover extending the linac energy with 1 or 2 GeV will give the opportunity to get closer to 1 Angstrom radiation with much more flexibility and better performances. Given these opportunities at the MAX IV laboratory, a free electron laser is envisaged in the long term perspective of the facility. In this study we investigate the case of a 5 GeV machine which can produce radiation in the X-ray region. The FEL design will benefit from the implementation of self-seeding, to enhance stability of the central wavelength and spectral bandwidth. Tapering along variable gap undulators will help to extract the maximum photon flux and increase the brilliance of the source. Among others, this kind of machine would be suitable for time resolved experiments and imaging.  
 
TUPEA058 The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation electron, laser, photon, linac 1265
 
  • J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Appleby, M. Serluca, G.X. Xia
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, A.M. Kolano
    University of Huddersfield, Huddersfield, United Kingdom
  • R. Bartolini, I.P.S. Martin
    Diamond, Oxfordshire, United Kingdom
  • N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • L.T. Campbell, B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
  • S. Chattopadhyay
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • D. Newton, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  
  The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.  
 
TUPEA059 CLARA Accelerator Design and Simulations linac, diagnostics, laser, emittance 1268
 
  • P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Science & Technology Facilities Council
We present the accelerator design for CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory. CLARA will be a testbed for novel FEL configurations. The accelerator will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. We describe the transport in detail including dedicated diagnostic sections. Beam dynamics simulations are then used to define a set of operating working points suitable for the different FEL schemes intended to be tested on CLARA. 		 
 
TUPEA060 Jitter Tolerance for CLARA linac, laser, electron, cathode 1271
 
  • B.P.M. Liggins, J.K. Jones, J.W. McKenzie, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Science & Technology Facilities Council
CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory will be a test-bed for novel FEL configurations. CLARA will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. Ensuring stability of the VUV radiation pulses is a key aim of the project. To this end, we investigate in detail the jitter tolerance of the machine. This will ultimately determine the pulse stability. 		 
 
TUPEA061 High-Brightness SASE Studies for the CLARA FEL undulator, electron, radiation, simulation 1274
 
  • R.N.C. Santer, N. Thompson
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The Compact Linear Accelerator for Research and Applications (CLARA) is a proposed 250 MeV FEL test facility to be constructed at STFC Daresbury Laboratory in the UK [1]. This paper presents study of a scheme for the temporal and spectral stabilisation of the SASE output. A feasibility study for the operation of the FEL in a novel High-Brightness SASE mode is presented. Electron beam delays are introduced between undulator sections to disrupt the localised collective FEL process, increase the radiation coherence length and reduce the rms bandwidth. This may extend the range of electron bunch lengths appropriate for the generation of temporally coherent single spike SASE FEL pulses.  
 
TUPEA074 Protection of VUV FEL Mirrors using Soft Orbit Bump at Duke FEL/HIGS facility radiation, wiggler, electron, dipole 1301
 
  • S.F. Mikhailov, H. Hao, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  
  Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033
The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. Presently, the energy range of the gamma-beam is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 1010 gammas per second around 10 MeV. Production of high intensity, high energy gamma-beams of 60 to 100 MeV, using UV-VUV mirrors of 240 to 190 nm, requires high energy, high current electron beams of 0.9 to 1.05 GeV. Synchrotron radiation damage to the FEL mirrors becomes crucial for VUV FEL operation at or below 190 nm. The edge radiation (ER) from the End-of-Arc (EOA) bending magnet, instead of the radiation of FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we describe a further development of the “soft” orbit bump concept to significantly reduce the radiation exposure to the mirror from the EOA dipole magnet. The bump uses designated "soft" orbit correctors with magnetic field limited to produce a radiation with a critical wavelength close or below the FEL wavelength. 		 
 
TUPEA086 Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source linac, emittance, electron, laser 1316
 
  • Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou
    SLAC, Menlo Park, California, USA
  • P. Emma
    LBNL, Berkeley, California, USA
  
  Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.  
 
TUPME027 Advanced Studies on New Generation of Electron-positron Accelerators and Colliders for Fundamental and Applied Researches laser, electron, radiation, gun 1631
 
  • A. Dudarev, N. Balalykin, U.A. Budagov, V. Kobets, M.V. Lyablin, B.M. Sabirov, G. Shirkov, E. Syresin, G.V. Trubnikov
    JINR, Dubna, Moscow Region, Russia
  
  JINR actively leads the R&D works in particle accelerator physics and engineering, construction of the free electron laser with the aim to prepare proposals for the project of JINR participation in international collaboration on construction of the future Linear Collider (CLIC/ILC). JINR scientists and engineers study in free electron laser physics, development and construction of systems applied for formation and diagnostics of ultra short dense bunches in the linear electron accelerators. JINR physicists also take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, and possible ILC location near Dubna.  
 
TUPME030 Emittance Reconstruction from Measured Beam Sizes emittance, coupling, simulation, optics 1640
 
  • J. Giner Navarro, A. Faus-Golfe, J. Fuentes, J. Navarro, J. Resta
    IFIC, Valencia, Spain
  
  In this paper we analyze the projected emittance (2D) and the intrinsic emittance (4D) reconstruction method by using the beam size measurements at different locations. We have studied analytically the conditions of solvability of the systems of equations involved in this process and we have obtained some rules about the locations of the measurement stations to avoid unphysical results. Presently, simulations are being made to test the robustness of the algorithm in realistic scenarios with high coupling and measurement errors. The special case of a multi-OTR system in ATF2 is being studied in much detail. The results of these studies will be very useful to better determine the location of the emittance measurement stations in the diagnostic sections of Future Linear Colliders.  
 
TUPME062 Simulation and Analysis of Microbunching Instability in a High Repetition rate FEL Beam Delivery System electron, laser, simulation, linac 1709
 
  • J. Qiang, J.N. Corlett, P. Emma, C.E. Mitchell, M. Venturini
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
Microbunching instability in the accelerator beam delivery system of an FEL can significantly degrade the electron beam quality and limit performance of the X-ray radiation. In this paper, we present detailed numerical simulation and analytical analysis of the microbunching instability in a high repetition rate X-ray FEL beam delivery system that is being studied at Lawrence Berkeley National Laboratory. Our results suggest that by using a flexible accelerator design and a laser heater, the effects of microbunching instability can be suppressed without significantly sacrificing the final electron beam quality. 		 
 
TUPWA057 Effects of Transient CSR Wakefields on Microbunching in a Bunch Compressor wakefield, impedance, lattice, radiation 1832
 
  • C.E. Mitchell, J. Qiang
    LBNL, Berkeley, California, USA
  
  Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The standard analytical model of CSR-induced microbunching in a bunch compressor chicane makes use of a steady-state 1-D model of the longitudinal CSR interaction. This model is numerically generalized to include the effects of transient CSR wakefields due to bend entry and exit, as well as CSR that is generated in upstream bends and propagates across one or more lattice elements before interacting with the beam. The resulting linear integral equation for CSR-induced microbunching is solved numerically for the second bunch compressor of a proposed Next Generation Light Source. 		 
 
TUPWA071 Studies of Resistive Wall Heating at JLAB FEL impedance, wiggler, resonance, electron 1868
 
  • R. Li, S.V. Benson
    JLAB, Newport News, Virginia, USA
  
  Funding: Work supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
When the JLAB FEL is under CW operation, it had been observed that temperature rises over the wiggler vacuum chamber, presumably as the result of the power deposition on the resistive wall of the wiggler chamber. Previous analyses have been done on the resistive wall impedance for various cases, such as DC, AC, and anomalous skin effects*. Here we report an investigation on the beam kinetic energy losses for each of these cases. This study includes the non-ultrarelativistic effect on resistive wall loss, for both round pipe and parallel plates. We will present the comparison of our results with the measured data obtained during CW operation of the JLAB FEL. Other possible factors contributing to the measured heating will also be discussed.
* K. Bane and G. Stupakov, SLAC-PUB-10707, 2004. 		 
 
TUPWO029 Beam Line Design at the CAEP THz Free Electron Laser electron, cavity, emittance, laser 1937
 
  • P. Li, W. Bai, H. Wang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  • X. Li
    TUB, Beijing, People's Republic of China
  
  China Academy of Physics (CAEP) is currently building a THz Free Electron Laser (THz-FEL) which serves as a radiation light sourse used for research in a variety of experimental fields. In this paper, we present the design of the beam line, which was accomplished using PARMELA and TRANSPORT code simulations. The accelerator consists of a 350 kV photocathode DC gun in conjunction with one cryomodule containing two 4-cell superconductiong RF cavities. The energy of the elctron beam is 7~8 MeV, and the maximum of the average beam current is 5 mA. A transverse emittance typically below 10 pi mm.mrad can be achieved.  
 
TUPWO035 Physical Design of Beam Transport Line of a Compact Terahertz FEL lattice, undulator, quadrupole, electron 1952
 
  • H. Zeng, Q.S. Chen, Q. Fu, B. Qin, B. Wu, Y.Q. Xiong
    HUST, Wuhan, People's Republic of China
  • G. Feng, Y.J. Pei
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  The single pass, linac-based compact terahertz source at HUST is now in the physical design stage. To match Twiss parameters and dispersion function of the electron beam at the undulator entrance and get smaller beta function in the whole line, several lattices based on the double bending achromat(DBA) structure were discussed and the optimized design is given with beam dynamics results–calculated by MAD and Trace 3D.  
 
TUPWO061 Design of a Soft Orbit Bump for FEL Mirror Protection at Duke FEL/HIGS Facility radiation, electron, synchrotron, synchrotron-radiation 2006
 
  • H. Hao, J.Y. Li, S.F. Mikhailov, Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  
  Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
In an oscillator Free-Electron Laser (FEL) with a high energy electron beam, it is critical to minimize harmful high-energy radiation on the downstream FEL mirror in order to increase its lifetime. At the High Intensity Gamma-ray Source (HIGS) facility at Duke University, effort has been devoted to developing a variety of techniques to reduce the amount of radiation on the FEL mirror. One of the most effective methods was the use of a set of adjustable in-vacuum apertures to block harmonic radiation from FEL wigglers. In recent studies, it was determined that the edge radiation from the end-of-the-arc bending magnet is the main source of UV/VUV and x-ray radiation which causes mirror damage. To mitigate this effect, a soft orbit bump is designed to change the displacement and angle of the electron beam around the end-of-the-arc area. This soft orbit bump is developed using the multi-objective optimization technique. Calculation shows the soft orbit bump can significantly reduce the flux of high energy photons on the FEL mirror. Study is also performed to determine the impact of this orbit bump on the injection, beam lifetime, and the FEL and gamma-ray operation at HIGS facility. 		 
 
WEZB102 Overview of Seeding Methods for FELs electron, radiation, undulator, laser 2063
 
  • S. Reiche
    PSI, Villigen PSI, Switzerland
  
  In recent years enormous progress has been achieved in the theoretical understanding and experimental demonstration of FEL seeding. The state of the art for FEL seeding should be reviewed and compared to HHG, HGHG, EEHG techniques. The potential of various seeding methods and their promise to produce radiation pulses that approach the transform limit in a range of experimental configurations at different user facilities should be explored.  
slides icon Slides WEZB102 [4.238 MB]  
 
WEODB101 X-ray Spectra and Peak Power Control with iSASE undulator, electron, laser, radiation 2068
 
  • J. Wu, F.-J. Decker, Y. Feng, J. Krzywinski, H. Loos, A.A. Lutman, A. Marinelli, H.-D. Nuhn, C. Pellegrini, D.F. Ratner, D.H. Zhang, D. Zhu
    SLAC, Menlo Park, California, USA
  
  Funding: Work is supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
We report the first measurement of spectral line-width reduction in a self-amplified spontaneous emission (SASE) X-ray free-electron laser (FEL) obtained by introducing repeated delays of the electron bunch with respect to the radiation field pulse. The improved longitudinal coherence obtained by this method reduces the intensity spiking effect characteristic of a SASE FEL. The electron-photon delays introduced along the FEL undulator mix the spikes phase and amplitude, increasing the cooperation length and generating a smaller bandwidth than in the conventional SASE mode of operation of an FEL. We call this mode of operation, based on repeated electron-photon delays, ‘‘improved SASE'' (iSASE). We also show with theoretical and simulation analysis that in the iSASE mode it is possible to choose the separation and magnitude of the delays to obtain a nearly transform limited X-ray pulse. This analysis is carried out using a time dependent, one-dimensional model and with GENESIS numerical simulation, including three-dimensional effects. 		 
slides icon Slides WEODB101 [7.647 MB]  
 
WEODB102 Generating Polarization Controllable FELs at Dalian Coherent Light Source polarization, controls, electron, undulator 2071
 
  • T. Zhang, H.X. Deng, D. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • D.X. Dai, G.R. Wu, X.M. Yang, W.Q. Zhang
    DICP, Dalian, People's Republic of China
  
  Funding: 973 Program of China (2011CB808300), NSFC 11175240 and 11205234.
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*.
*T. Zhang, et al., FEL Polarization Control Studies on Dalian Coherent Light Source, Chinese Physics C, 2013, to be published. 		 
slides icon Slides WEODB102 [6.131 MB]  
 
WEODB103 Current Status of PAL-XFEL Project undulator, emittance, gun, klystron 2074
 
  • H.-S. Kang, J.H. Han, T.-H. Kang, C. Kim, D.E. Kim, S.H. Kim, I.S. Ko, H.-S. Lee, K.-H. Park, S.J. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  The PAL-XFEL is a 0.1-nm hard X-ray FEL construction project which started from 2011 with a total budget of 400 M$. The PAL-XFEL is designed to have three hard X-ray undulator lines at the end of 10-GeV linac and a dog-leg branch line at 3 GeV point for two soft X-ray undulator lines. The three-bunch compressor lattice (3-BC) is chosen to have large flexibility of operation, making it possible to operate soft X-ray FEL undulator line simultaneously and independently from hard X-ray FEL line. Self seeding to achieve the FEL radiation bandwidth of below 5x10-5 is baseline for the hard X-ray FEL line. Polarization control will be available by using the PU + EPU layout for the soft X-ray FEL line. The overview of the project with current status is presented.  
slides icon Slides WEODB103 [8.332 MB]  
 
WEOBB201 Commissioning of the X-band Transverse Deflector for Femtosecond Electron/X-Ray pulse Length Measurements at LCLS undulator, electron, diagnostics, klystron 2091
 
  • Y.T. Ding, C. Behrens, J.C. Frisch, Z. Huang, P. Krejcik, J.R. Lewandowski, H. Loos, J.W. Wang, M.-H. Wang, J.J. Welch
    SLAC, Menlo Park, California, USA
  • C. Behrens
    DESY, Hamburg, Germany
  
  X-ray free-electron lasers provide ultrashort x-ray pulses from several to a few hundred femtoseconds for multidisciplinary users. However, tremendous challenges remain in the measurement and control of these ultrashort pulses with femtosecond precision, for both the electron beam and the x-ray pulses. A new diagnostic scheme adding a transverse radio-frequency deflector at the end of the linac coherent light source (LCLS) undulator beamline has been proposed*. Two 1-m long deflecting structures have been installed at LCLS during the summer of 2012. Installation of the high power RF components including the klystron, waveguide, RF controls etc. is proceeding and commissioning is scheduled for March 2013. We report the latest progress of the commissioning of the deflector at LCLS.
* Y. Ding et al., Phys. Rev. ST Accel. Beams 14, 120701 (2011) 		 
slides icon Slides WEOBB201 [4.199 MB]  
 
WEIB204 Industry and Science, POSCO and POSTECH Case linac, site, klystron, storage-ring 2115
 
  • W. Namkung
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: * Supported by MEST and POSTECH
POSCO is a world-leading iron and steel company established in 1968 in Pohang, in the South East coast of Korea. Starting with 1.0 million ton size in 1973, the company made profits even in the first year. While its capacity has been increased to 40 million tons with another works in Gwangyang, POSCO paid attention on education to attract intellectuals to Pohang and Korea. It results in establishing a small-sized university, Pohang University of Science and Technology (POSTECH) in 1987. POSTECH immediately decided to construct a third generation synchrotron light source of 2.0 GeV, Pohang Light Source (PLS) on its campus in 1988, with support from POSCO and also Government. POSTECH achieved a high rank in the world, and PLS is upgraded to 3.0 GeV in 2011. A new PAL-XFEL of 10.0 GeV is now under construction. POSCO's consistent policy is the key of the success of POSTECH and Pohang Light Source. This is an unprecedented example of the relationship between industry and science. 		 
slides icon Slides WEIB204 [4.759 MB]  
 
WEPWA023 Design of 14 MeV LINAC for THz Source Based FEL gun, linac, quadrupole, emittance 2181
 
  • Y.J. Pei, G. Feng, Y. Hong, G. Huang, D. Jia, K. Jin, C. Li, J. Li, S. Lu, L. Shang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • Q.S. Chen, M. Fan, T. Hu, Y.Q. Xiong, H. Zeng
    HUST, Wuhan, People's Republic of China
  • B. Qing, Z.X. Tang, X.L. Wei
    USTC, Hefei, Anhui, People's Republic of China
  • L.G. Shen, F. Zhang
    USTC/PMPI, Hefei, Anhui, People's Republic of China
  
  Abstract THz wave have many special performances, such as it can penetrate deep into many organic materials without the damage associated with ionizing radiation such as X-ray, it can be used to distinguish between materials with varying water content, because THz radiation is absorbed by water. In part researchers lacked reliable sources of THz, so develop new THz sources is important now. So far there were many kind of THz Source, one of them is THz source based a FEL that can produce high power (~kW). This paper will describe the design of a LINAC of 14MeV which is used for FEL to produce THz radiation. The LINAC is mainly composed of a novel EC-ITC RF gun, compensation coil, constant gradient accelerating structure, beam diagnostic system and so on. Main design parameters are as following: Energy 7~15MeV Beam current (macro pulse) 571mA (micro pulse) 30~40° Bunch length 5~7ps Charge per bunch 200~300pC Normalized emittance ≤10mm.mrad Energy spread(rms) ≤0.5%  
 
WEPWA037 Effect of Ground Vibration on the Out-coupled Power in a Terahertz FEL Oscillator cavity, simulation, alignment, laser 2211
 
  • Q. Fu, L.Z. Deng, B. Qin, P. Tan, Y.Q. Xiong, Y.B. Yibin, H. Zeng
    HUST, Wuhan, People's Republic of China
  
  To acquire high power out-coupled, we must ensure the co-axis of electron orbit, optical beam and magnetic field. The propagation of ground vibration through the optical platform will lead to misalignment of the optical axis in the FEL optical cavity. Based on measurement results of the ground vibration, simulations of misalignment are studied with GENESIS+OPC. The tolerance of mirror tilt and offset is also discussed.  
 
WEPWA038 Influence of Magnet Errors and Waveguide Permeability on Magnetic Field Performance in Pure Permanent Undulators undulator, permanent-magnet, simulation, radiation 2214
 
  • X. Liu, K.F. Liu, B. Qin, P. Tan, B. Wu, Y.Q. Xiong, J. Yang, L. Yang
    HUST, Wuhan, People's Republic of China
  
  Abstract For pure permanent magnet (PM) undulator, unavoidable divergences of remanence field and magnetization vector in PM blocks and installation error will cause magnetic field error at the central line of the undulator. This paper presents the simulation results of the magnetic field in non-ideal undulator containing these errors, with specified tolerances in Normal distribution. As well as the peak field error, increases of the harmonic components and impact on field integrals are calculated. The influence on magnetic field caused by waveguide permeability is also discussed.  
 
WEPWA040 Options for PAL-XFEL Injector Operation emittance, laser, gun, cathode 2217
 
  • J.H. Han
    PAL, Pohang, Kyungbuk, Republic of Korea
  • M.S. Chae
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  Present designs of the PAL-XFEL injector assume a 120 MV/m peak field at the cathode in the gun and a flat-top longitudinal drive-laser profile. As accelerating field in the gun decreases and laser shape becomes imperfect, beam quality degradation takes place. On the other hand, by reducing accelerating field in the gun and by relaxing drive-laser shaping requirement the stability of the injector can be increased. We study various options for operating conditions of the injector with relaxed RF and drive-laser parameters.  
 
WEPWA061 ALICE ERL Intra-train Variation Investigation using Bunch-by-bunch BPMs laser, cathode, linac, gun 2256
 
  • D. Angal-Kalinin, F. Jackson, S.P. Jamison, J.K. Jones, A. Kalinin, T.T. Thakker, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The ALICE ERL is an energy recovery test facility based at Daresbury Laboratory. We present investigations of charge and transverse variations/oscillations in the ALICE trains (up to 1600 bunches, spacing 55.2ns, bunch charge up to 60pC), using turn-by-turn EMMA BPMs adjusted for bunch-by-bunch measurements*. A set-up was established which allows use of pickups immediately downstream of the DC Gun as well as in the Arcs. To analyse variations, a DFT was used. It was established that a previously observed prominent (~10%) 300kHz charge envelope variation is a feature of the Photoinjector Laser. A set of transverse variations at 300kHz and below that depended on steering was also observed in the Injection Line. Downstream of the Booster, it was discovered that the transverse spectra are different. Prevailing quite regular variations (in range of 50um) were observed around 100kHz, manifesting themselves in the horizontal plane, present in non-dispersive regions, and dependent on trajectory offset in the Booster. We discuss the results, and also present our plans to apply this technique to a new single bunch injector EBTF now under commissioning in Daresbury Laboratory.
* A. Kalinin et al, MOPA30, IBIC12, Tsukuba, Japan. 		 
 
WEPWA063 Longitudinal Beam Transport in the ALICE IR-FEL Facility sextupole, quadrupole, dipole, linac 2262
 
  • F. Jackson, D. Angal-Kalinin, J.K. Jones, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  
  The ALICE facility at Daresbury Laboratory is an energy recovery test accelerator which includes an infra-red oscillator-type free electron laser (IR-FEL). The longitudinal transport functions (including R56 and T566) in the ALICE accelerator lattice are studied in this paper by use of precision time-of-arrival methods. The results allow characterisation of the triple bend achromat (TBA) arcs and compression chicane of the lattice. The relevance of the results to the operational performance of ALICE as a IR-FEL facility and a THz source is discussed.  
 
WEPWA064 Simulations of the ALICE ERL linac, simulation, electron, space-charge 2265
 
  • J.K. Jones, D.J. Dunning, F. Jackson, J.W. McKenzie, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  ALICE is a low-energy Energy Recovery Linac operated at Daresbury Laboratory in Cheshire, UK. The ALICE injector is based around a 350 kV DC photo-cathode electron gun. With an operating voltage of 325 keV, electron dynamics in the ALICE injector are space-charge dominated and highly non-linear, and this complicates simulations of the beam dynamics in this region. With an intermediate energy of 6.5 MeV, and a final ring energy of 27.5 MeV, the space-charge effects in the rest of the machine can also not be ignored. In this paper we summarise some of the work that has been performed to understand and optimise the simulations of the ALICE ERL, in several different operating modes, and using several different modelling codes.  
 
WEPWA069 Design Concepts for an RF Deflecting Cavity-Based Beam Spreader for a Next Generation FEL cavity, dipole, gun, septum 2274
 
  • M. Placidi, L.R. Doolittle, P. Emma, J.-Y. Jung, J. Qiang, A. Ratti, C. Sun
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The Lawrence Berkeley National Laboratory (LBNL) is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. Electron bunches supplied by a high-brightness, high-repetition-rate photocathode electron gun are distributed by a beam spreader, designed to deliver individual bunches from a CW linac to an array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. We describe recent developments in the technical choices, design and parameters of the spreader system and its main components. 		 
 
WEPWA075 High-gain X-ray FELs using a Transverse Gradient Undulator in an Ultimate Storage Ring undulator, emittance, electron, storage-ring 2286
 
  • Y.T. Ding, P. Baxevanis, Y. Cai, Z. Huang, R.D. Ruth
    SLAC, Menlo Park, California, USA
  
  An “ultimate” storage ring based on PEP tunnel has been designed to achieve diffraction limited emittance (at 1.5 Angstrom)[*]. With sufficient peak current, the beam brightness of such an “ultimate” storage ring may be sufficient to drive a short-wavelength, high-gain FEL. However, the large energy spread intrinsic to storage rings hinders the FEL applications for x-ray wavelengths. To overcome this problem, we adopt the transverse-gradient undulator concept[**][***] to study a high-gain FEL in an ultimate storage ring. Using PEP-X as an example, we showed from simulations that a high-gain FEL at the photon energy 1keV with a peak power of a few hundred megawatts can be achieved within a saturation length of 100 meters.
* Y. Cai et al., Phys. Rev. ST Accel. Beams 15, 054002 (2012).
** T. Smith et al., J. Appl. Phys. 50, 4580 (1979)
*** Z. Huang, Y. Ding and C. B. Schroeder, Phys. Rev. Lett 109, 204801 (2012). 		 
 
WEPWA077 Aperture Test for Internal Target Operation in the JLAB High-current ERL target, electron, diagnostics, radiation 2289
 
  • S. Zhang, S.V. Benson, G.H. Biallas, K. Blackburn, J.R. Boyce, D.B. Bullard, J.L. Coleman, J. Delk, D. Douglas, P. Evtushenko, C.W. Gould, J.G. Gubeli, F.E. Hannon, D. Hardy, C. Hernandez-Garcia, K. Jordan, J.M. Klopf, R.A. Legg, M. Marchlik, W. Moore, G. Neil, J. Powers, T. Powers, D.W. Sexton, M.D. Shinn, C. Tennant, R.L. Walker, G.P. Williams, F.G. Wilson
    JLAB, Newport News, Virginia, USA
  • J. Balewski, J. Bernauer, W. Bertozzi, R.F. Cowan, P.F. Fisher, E. Ihloff, A. Kelleher, R. Milner, L. Ou, B.A. Schmookler, c. Tschalär
    MIT, Cambridge, Massachusetts, USA
  • N. Kalantarians
    Hampton University, Hampton, Virginia, USA
  
  Funding: Supported by the Commonwealth of Virginia, U.S. DOE Nuclear and High Energy Physics, and by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177.
A high current beam transmission test has been successfully completed at the JLAB FEL Facility, culminating in very low-loss transmission of a high current CW beam through a small aperture. The purpose of this test was to determine if an ERL is capable of meeting the stringent requirements imposed by the use of a 1018/cm3 internal gas target proposed for the DarkLight experiment*. Minimal beamline modifications were made to create a machine configuration that is substantially different from those used in routine UV or IR FEL operation. A sustained (8 hour) high power beam run was performed, with clean transmission through a 2 mm transverse aperture of 127 mm length simulating the target configuration. A beam size of 50 um (rms) was measured near the center of the aperture. Experimental data from a week-long test run consistently exhibited beam loss of only a few ppm on the aperture while running 4.5 mA current at 100 MeV – or nearly 0.5 MW beam power. This surpassed the users’ expectation and demonstrated a unique capability of an ERL for this type of experiments. This report presents a summary of the experiment, a brief overview of our activities, and outlines future plans.
References:
* P. Fisher, et al.,“Jlab PR-11-008: A Proposal for the DarkLight Experiment at the Jefferson Laboratory Free Electron Laser.” http://www.jlab.org/expprog/proposals/11prop.html 		 
 
WEPFI036 R&D on a Main Accelerating Section of a Compact THz-FEL electron, laser, simulation, radiation 2780
 
  • W. Bai, M. Li, X. Shen, H. Wang, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  In order to develop a tera-hertz(THz) radiation source and to make scientific researches on application of THz technology, a study on tera-hertz source is performed. The radiation source is based on technology of free electron laser(FEL). The energy booster section of the injector uses a 9 Cell standing wave accelerator as the main accelerator for the FEL. The accelerator works at S band.(2856 MHz), excited by a microwave power of about 3.5 MW. At the end of the accelerator, the high quality beam energy is of 6.5MeV ~ 7 MeV, and the current about 300 mA. This paper presents the newly prgress of the , as well as the working condition of the main accelerator.  
 
WEPFI038 R&D of New C-band Accelerating Structure for SXFEL Facility cavity, impedance, wakefield, linac 2785
 
  • W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • L. Chen, X. Sheng
    BVERI, Beijing, People's Republic of China
  • D.C. Tong
    TUB, Beijing, People's Republic of China
  
  C-band high gradient accelerating structure is crucial technology for Shanghai Soft X-ray FEL facility. Based on the prototype, the optimized C-band accelerating structure is proposed, and the experimental model is ready for high power test. In this paper, optimization design and some experiment results are presented, also design, fabrication and cold test of experimental model are introduced.  
 
WEPFI039 New X-band Deflecting Cavity Design for Ultra-short Bunch Length Measure of FEL at SINAP cavity, simulation, electron, impedance 2788
 
  • J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  
  For the development of Free Electron Lasers (FEL) at SINAP, ultra-short bunch is the crucial requirement for excellent lasing performance. It’s big challenge for deflecting cavity to measure the length of ultra-short bunch, and higher deflecting gradient is required for higher measurement resolution. X-band travelling wave deflecting structure has features of higher deflecting voltage and compact structure, which is good performance at ultra-short bunch length measuring. In this paper, a new X-band deflecting structure was designed, operated at HEM11- 2π/3 mode. For suppressing the polarization of deflection plane of the HEM11 mode, two symmetrical caves are added on the cavity wall to separate two polarized modes. More details of design and simulation results are presented in this paper.  
 
WEPFI040 R&D of C-band Pulse Compression for Soft X-ray FEL at SINAP cavity, coupling, simulation, klystron 2791
 
  • C.P. Wang, W. Fang, Q. Gu, W.C. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  
  A compact Soft X-ray Free Electron Lasers facility is presently being constructed at SINAP, and 8 C-band accelerating structure unit are required for third-stage including 4 pulse compressors. The field mode of C-band SLED is TE0.1.15 with high quality factor Q, and the coupling coefficient is 8.5. Based on the design, the power pulse of klystron is compressed from 2.5μs to 0.5μs, and finally the power gain is about 3.1. In this paper, the details and simulation of 3-dB coupler, mode convertors and the resonant cavities are presented, meanwhile some cold test results of cavity are also analyzed at the end of this paper.  
 
WEPFI043 S-band High Stability Solid State Amplifier for 10 GeV PAL-XFEL LLRF, controls, klystron, monitoring 2800
 
  • W.H. Hwang, J.Y. Huang, H.-S. Kang, H.-S. Lee, W.W. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 60 Hz. And the specifications of the rf phase and amplitude stability are 0.05 degrees(rms) and 0.05%(rms) respectively. The SSA(Solid State Amplifier) is used for driver of 80MW Klystron. The output power of SSA is 800W. Also, the measured rf stability of SSA output is 0.03 degrees rms and 0.025 % rms. This paper describes the microwave system and the SSA for the PxFEL.  
 
WEPME019 Development of Beam Position Feedback Control System in KU-FEL feedback, gun, controls, electron 2968
 
  • H. Ohgaki, Y.W. Choi, H. Imon, T. Kii, R. Kinjo, T. Konstantin, K. Masuda, H. Negm, K. Okumura, M. Omer, S. Shibata, K. Shimahashi, K. Yoshida, H. Zen
    Kyoto University, Institute for Advanced Energy, Kyoto, Japan
  
  The stability of electron beam parameters such as position, energy etc. is very crucial for stable FEL operation. In Kyoto University MIR-FEL facility (KU-FEL), fluctuation of beam position and energy is caused by external fluctuations, such as the fluctuation in the cathode temperature of the thermionic RF-gun due to the back-streaming electrons, fluctuation of RF phase and amplitude, fluctuations of room and water temperatures, electric noises and so on. To monitor electron beam movement, we have already developed BPM system consisting of a 4-button electrode type BPM, a heterodyne detector, and CAMAC ADC in KU-FEL. By using this BPM system we have observed some correlations between external fluctuations and the beam position movements. In this conference, we will present the developed BPM system as well as the beam feedback system for stable KU-FEL operation.  
 
THOAB103 Phase Space Tomography Research at Daresbury quadrupole, space-charge, electron, simulation 3096
 
  • K.M. Hock, D.J. Holder, M.G. Ibison, B.D. Muratori, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  We report on the progress of phase space tomography research at Daresbury. The efforts over the past three years have been focussed on measuring the electron beam at the ALICE tomography section. Based on this result, we have developed techniques for improving resolution using normalised phase space, removing streaking artefacts by thresholding, demonstrating reliability of reconstructed phase space. We have developed in-house reconstruction codes using both the Filtered Back Projection and the Maximum Entropy Techniques. We are currently using a combination of simulation and measurements to investigate the onset of space charge effects at low bunch charges over short distances.  
slides icon Slides THOAB103 [0.878 MB]  
 
THPPA02 Features and Applications of the Program ELEGANT simulation, electron, linac, lattice 3139
 
  • M. Borland
    ANL, Argonne, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
ELEGANT is an open-source accelerator design and simulation code that has been in use and development for nearly two decades. In that time, it has evolved into a fairly general code for the design and modeling of linacs and storage rings, due in no small measure to suggestions and feedback from users world-wide. The code is best known for modeling of linacs for free electron lasers and particularly its relatively fast and straightforward modeling of coherent synchrotron radiation in magnetic bunch compression systems. This capability led to the discovery of a microbunching instability in such systems, thus helping to seed a new field of research. ELEGANT's capabilities are enhanced by the use of self-describing data files and the Self-Describing Data Sets (SDDS) toolkit. In this paper, we briefly review the features and capabilities of the code, then give a series of application examples from simulation of linear accelerators and storage rings. 		 
slides icon Slides THPPA02 [0.477 MB]  
 
THPEA024 The Control System of the SDUV-FEL Test Facility controls, EPICS, PLC, power-supply 3195
 
  • J.G. Ding, S.M. Hu, G.Y. Jiang, H.F. Miao, H. Zhao, H.J. Zhu
    SINAP, Shanghai, People's Republic of China
  
  At SINAP, the Shanghai deep ultraviolet FEL test facility (SDUV FEL) was integrated to test the FEL key technologies and principles. The facility was constructed based on the existed SINAP 100MeV LINAC with modifications of cathode gun replacement and magnet compressor segment increment, extension of the undulator section, and the seeded laser system. The control system of the facility has been developed which upgraded and extended from the existed LINAC control system. The system was integrated based on the EPICS toolkit, consists of several subsystems of magnet power supply control, timing, vacuum monitor, RF control, undulator gap adjustment, and machine protection system. In this paper, the SDUV FEL control system is introduced. Solutions of equipment control, hardware and software implementations, and system integrations are described in details.  
 
THPEA057 Compensation Schemes for Operation of FEL Wigglers on Duke Storage Ring wiggler, storage-ring, lattice, quadrupole 3270
 
  • J.Y. Li, H. Hao, S.F. Mikhailov, V. Popov, W. Wu, Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  
  Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
The Duke FEL is the photon driver for the High Intensity Gamma-ray Source (HIGS). To extend the capabilities of the FEL and HIGS to higher photon energy regions, a FEL wiggler switchyard system was developed in the recent years. This system was installed and commissioned in 2012. The FEL wiggler switchyard is used to change between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight section in a short period of time (a few days). With a total of six electromagnetic wigglers, the Duke FEL can be operated in a number of wiggler configurations and with a wide range of magnetic fields. The operation of uncompensated FEL wigglers can cause significant changes to the electron beam closed orbit and magnetic lattice. To maintain a sufficiently large dynamic aperture for an efficient injection and good beam lifetime, a set of complex compensation schemes, including magnetic field and lattice compensation, have been developed for the operation of the FEL wigglers. This paper reports the overall architecture and performance of the FEL wiggler compensation schemes and their implementation in the accelerator controls system using the feedforward mechanism. 		 
 
THPEA062 Magnetic Field Measurements for the IAC-RadiaBeam THz Project dipole, quadrupole, radiation, electron 3282
 
  • P. Buaphad, Y. Kim, M. Williams
    ISU, Pocatello, Idaho, USA
  • A. Andrews, T. Downer, C.F. Eckman, Y. Kim, M. Smith
    IAC, Pocatello, IDAHO, USA
  
  At the Idaho Accelerator Center (IAC) of Idaho State University, recently, a new chicane with four dipoles and quadrupole triplet magnets were installed in a 44 MeV linac to perform the IAC-RadiaBeam Terahertz (THz) project. To generate high power THz radiation, a THz radiator with numerous periodic gratings was also installed downstream of the quadrupole triplet. However, the electron beam shape at the radiator has to be horizontally focused strip-like one due to a tiny radiator gap with a width of 1.2 mm, and electron bunch length should be about a few picosecond (ps) to generate high power THz radiation in the radiator. By using the quadrupole triplet and chicane dipoles, we can control the transverse beam profile and bunch length freely. In this paper, we report the measured field maps of the dipole and quadrupole magnets, their effective lengths, and field strength or gradient as a function of the magnet power supply current.  
 
THPFI010 High Energy RF Deflectors for the FERMI@Elettra project electron, linac, vacuum, wakefield 3309
 
  • M. Dal Forno, S. Biedron, D. Castronovo, P. Craievich, S. Di Mitri, D. La Civita, G. Penco, M. Petronio, F. Pradal, L. Rumiz, L. Sturari, D. Wang, D. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  • M. Dal Forno, M. Petronio, R. Vescovo
    University of Trieste, Trieste, Italy
  • N. Faure
    PMB-ALCEN, PEYNIER, France
  
  Measuring and controlling the longitudinal phase space and the time-slice emittance of the electron bunch at 1.2 GeV entering in the undulator beam-lines, is crucial to obtain high FEL performances. In the FERMI@Elettra machine, two RF deflecting cavities have been installed at the end of the linac, in order to stretch the electron bunch horizontally and vertically, respectively. The two cavities are individually powered by the same klystron and a switch system is used to choose the deflection plane. This paper reports the RF measurements carried out during the acceptance test, the RF conditioning including the breakdown rate measurements. Finally, the commissioning with electron beam of the deflecting structure and a comparison of the measured electron bunch length evaluated by using the two deflectors are also reported.  
 
THPFI047 Design Guidelines for Ferrite Absorbers Submitted to RF-induced Heating radiation, damping, HOM, pick-up 3394
 
  • A. Bertarelli, M. Garlaschè
    CERN, Geneva, Switzerland
  
  The use of ferrite absorbers is one of the most effective means of damping potentially harmful high order RF modes, which may lead to beam instabilities and excessive power losses in accelerator devices. However, the power deposited on ferrite absorbers themselves may lead to ferrite exceeding its Curie temperature, losing its damping properties. An evaluation of the ferrite capability to dissipate deposited heat is hence of paramount importance for the safe design of particle accelerator devices. In this paper, figures of merit are proposed to assess the maximum specific power allowed on a generic ferrite tile, before it reaches its Curie temperature. Due to its inherent brittleness, sufficient contact pressure between ferrite and its housing, allowing heat transmission by conduction, can hardly be applied. A semi-analytical study is thus performed, assuming that ferrite is evacuating heat solely through radiation. The described method is then exemplified in the case of the BPM-embedded tertiary collimator (TCTP) designed in the framework of the LHC collimation upgrade.  
 
THPME018 Design of Dipole and Quadrupole for THz-FEL at CAEP quadrupole, dipole, beam-transport, magnet-design 3540
 
  • L.G. Yan, W. Bai, D.R. Deng
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  The high average power terahertz free electronic laser (THz-FEL) is being constructed at CAEP (China Academy of Engineering Physics), which is designed for lasing between 100-300 μm. The magnets of THz-FEL include 3 dipoles and 6 quadrupoles, and their fields and field quality were required by 6-9 MeV operation. This proceeding introduced the design and the main parameters of these magnets. The higher harmonic content of the magnetic field was also analyzed. All the design of magnets achieved the goal.  
 
THPME026 First Results of the PAL-XFEL Prototype Undulator Measurements undulator, controls, radiation, insertion-device 3561
 
  • D.E. Kim, H.S. Han, Y.-G. Jung, H.-G. Lee, S.B. Lee, W.W. Lee, K.-H. Park, H.S. Suh
    PAL, Pohang, Kyungbuk, Republic of Korea
  • M.-H. Cho, I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. The hard X-ray undulator features 7.2 mm min magnetic gap, and 5.0 m magnetic length with maximum effective magnetic field larger than 0.908 T to achieve 0.1nm radiation at 10 GeV electron energy. A prototype for PAL-XFEL Xray undulator line is completed and the measurement, correction results are summarized.  
 
THPME027 Design and Fabrication of Prototype Phase Shifter for PAL XFEL undulator, electron, controls, radiation 3564
 
  • H.-G. Lee, Y.-G. Jung, H.-S. Kang, D.E. Kim, S.B. Lee, W.W. Lee, K.-H. Park, H.S. Suh
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Prototype phase shifters are being developed to be used for the X-ray and Soft X-ray undulator line. The phase shifters will be used to adjust the phase of the electron beam with respect to that of the radiation field. Two prototype phase shifters are being developed. One is based on the EU-XFEL phase shifter using zero-potential iron yoke, and the other one is similar to FERMI phase shifter where only permanent magnets are used. Driving system consists of 5 phase stepping motor, left/right handed ball screw and absolute linear encoder. In this paper, we describe the design, fabrication and test results of the two phase shifter prototypes.  
 
FRYAA01 An Overview of Light Source Development in Asia synchrotron, radiation, electron, linac 4005
 
  • D. Wang
    SINAP, Shanghai, People's Republic of China
  
  This talk should cover the history of light sources that have been constructed, are now in operation or planned for the future in Asia. Advances in accelerator physics and technological innovations leading to steadily increasing machine performance and photon beam properties should be discussed.  
slides icon Slides FRYAA01 [7.342 MB]