Electron Accelerators and Applications
Electron linac projects
Paper Title Page
MOPO004 Commissioning of the SRF Booster Cavity for LEReC 40
 
  • W. Xu, A.V. Fedotov, T. Hayes, D. Holmes, G.T. McIntyre, K. Mernick, S.K. Seberg, F. Severino, K.S. Smith, R. Than, Q. Wu, B. P. Xiao, T. Xin, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
One important component for LEReC project is a 704 MHz booster cavity, which was modified from the BNL ERL 704 MHz SRF gun cavity. The major modifications include converting the upstream cathode transportation to a proper beam pipe, adding a HOM coaxial line HOM damper to the downstream, retracting FPC insertions, and improvement of cryomodule layout. In the past one and half year, tremendous work was completed: the cavity was modified and tested vertically, FPC were conditioned, and HOM damper were designed and conditioned, cryomodule was re-assembled. The booster cavity cryomodule was successfully commissioned in mid October, and it was moved to LEReC location at RHIC tunnel 2 O’clock early November. This paper will report the configuration of the new cryomodule and its commissioning results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO004  
About • paper received ※ 22 August 2018      issue date ※ 18 January 2019  
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MOPO005 Commissioning of the Normal Conducting Cavities for LEReC Project 44
 
  • B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is designed, and is currently under commissioning at BNL. The linac of LEReC consists of a DC photoemission gun, a 704 MHz superconducting radio frequency (SRF) booster cavity, a three-cell 2.1 GHz third harmonic cavity for RF curvature correction, a single-cell 704 MHz cavity for energy de-chirping and a 704 MHz deflecting cavity for diagnostic line. In this paper, we present the commissioning of three normal conducting cavities mentioned above.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO005  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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MOPO006 Crosstalk Effect in the LEReC Booster Cavity 47
 
  • B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
The Linac of Low Energy RHIC electron Cooler (LEReC) is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with peak-to-peak dp/p less than 7·10-4. The booster cavity is the major accelerating component in LEReC, which is a 0.4 cell cavity operating at 2 K, with a maximum energy gain of 2.2 MeV. It is modified from the Energy Recovery Linac (ERL) photocathode gun, with fundamental power coupler, pickup coupler and HOM coupler close to each other. Crosstalk effect in this cavity is simulated and measured. Correction method is proposed to meet the energy spread requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO006  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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MOPO007 The Developing of the Beam Injection Section with Laser Source and S-Band Electron RF Gun for SuperKEKB Project 50
 
  • X. Zhou, Y. Ogawa, M. Yoshida, R. Zhang
    KEK, Ibaraki, Japan
 
  For the beam injection at Linac Accelerator of the SuperKEKB project, the s-band RF gun needs to provide low-emittance high-charge electron bunches. An ultrashort high energy solid laser driving a cathode in a quasi-travelling side-coupled RF gun were developed. A Yb fiber and Nd:YAG hybrid laser amplify system is start with 114.24 MHz oscillator that synchronized from accelerator. Two beam lines with the 25Hz, ~20ps, and sub-mJ Ultraviolet pulses were generated to RF gun. Ir5Ce has long lifetime and quantum efficiency QE that was employed to cathode. The RF gun has two side coupled cavities on same axis can realize quasi-traveling wave, which is suitable for the high charge and low emittance beam generation. Now, great progress has been made to make the RF gun function well. For the Phase II commissioning, required charge and emittance were achieved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO007  
About • paper received ※ 05 September 2018      issue date ※ 18 January 2019  
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MOPO008 The RF Gun Adopting the Dielectric Assist Accelerating Structure 54
 
  • S. Mori, D. Satoh, M. Yoshida
    KEK, Ibaraki, Japan
 
  We apply the dielectric assist accelerating (DAA) structure to the RF gun, which is a candidate for a high average current and high brightness electron source. The DAA structure consists of ultralow-loss dielectric cylinders and disks which are periodically arranged in a metallic enclosure. Due to the high quality factor and the high shunt impedance of the DAA cavity, the RF gun adopting the DAA cavity can be a high-duty electron beam source at room temperature. We provide design work for RF gun adopting the DAA structure.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO008  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO009 ELI-NP Gamma Beam System - Current Project Status 59
 
  • P.S. Tracz
    IFIN-HH, Bucharest - Magurele, Romania
 
  The Gamma Beam System at the ELI-NP under construction in Magurele/Bucharest Romania, aims at producing high brilliance gamma-rays based on the laser Compton back-scattering, up to 3.5 and 19.5 MeV out of two interaction chambers. The design of warm RF electron linac is optimized to meet the unique source specification i.e. high brilliance, small relative bandwidth, tunable energy, and high spectral density. Together with technological development in field of high energy/high quality lasers it will open new opportunities for nuclear physics research in fields like nuclear photonics, nuclear astrophysics, photo-fission, and production of exotic nuclei, applications in industry, medicine, and space science. S-band laser driven RF photo-gun and two accelerating structures constitute the injector. The beam is then accelerated by C-band linac up to 350MeV (low energy linac), and up to 720MeV (high energy linac). The GBS was designed and is being constructed by the EuroGammaS - a consortium of European academic and research institutions and industrial partners. This paper gives an overview of the facility, describes the main linac systems and summarizes the project status.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO009  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO010 JINR Photocathode Research: Status and Plans 62
 
  • M.A. Nozdrin, N. Balalykin, J. Huran, V.F. Minashkin, G. Shirkov
    JINR, Dubna, Moscow Region, Russia
  • E. Gacheva, A. Poteomkin, V. Zelenogorsky
    IAP/RAS, Nizhny Novgorod, Russia
  • J. Huran
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
 
  Photocathode research in the frame of the "transmission" photocathode conception (backside illuminated cathode based on a quartz/sapphire plate or a metal mesh which is a substrate for thin film made of a photomaterial) is being conducted in the Veksler and Baldin Laboratory of High Energy physics (LHEP) of the Joint Institute for Nuclear Research (JINR). Status of the 30-kev DC Photogun test bench and recent results of the extremely thin carbon film based cathodes research are described. Progress in the full-scale photoinjector prototype (max electron energy of 400 keV) is given. Startup of the photoinjector was performed, 70 keV electrons were extracted (650 pC).  
poster icon Poster MOPO010 [1.564 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO010  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO016 Narrow-Band Terahertz Generation from Beam Pipe with Helix Wires 65
 
  • D. Wang
    TUB, Beijing, People’s Republic of China
 
  We studied through analysis and numerical simulations the use of a relativistic electron bunch to drive a metallic beam pipe with helix wire inside, for the purpose of gen-erating narrow-band terahertz radiation. we have shown that the frequency is related to the radius of the pipe and that of the wire, thus one can generate a narrow-band radiation pulse with frequency tunable through this scheme with different pipes and wires. The total energy of a few milli-Joules. The pulse length tends to be on the order of hundreds of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp.
*wangdan2016@mail.tsinghua.edu.cn
*yanlx@mail.tsinghua.edu.cn
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO016  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO018 Development of an Improved Capture Section for the S-DALINAC Injector* 68
 
  • S. Weih, M. Arnold, J. Enders, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • D.B. Bazyl, H. De Gersem, W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  For the injector of the superconducting Darmstadt electron linear accelerator S-DALINAC, the design of a new capture cavity was recently completed. This beta-reduced structure will optimize the capture of low-energy electron bunches from the gun section and therefore improve the longitudinal beam quality of the injector beam, as simulations have shown. The existing cryomodule of the injector has to be modified for the installation of the new cavity. These modifications include adaptions of the tuner frame as well as modifications of other surrounding parts. To improve the diagnostics in the low-energy section, an energy-spread measurement setup is currently also under development. In this contribution the cryomodule modifications as well as simulation results for the longitudinal beam dynamics are presented.
*Work supported by DFG through GRK 2128 "AccelencE"
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO018  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO019 Study on Cleaning of Copper Plated Bellows for LCLS-II 71
 
  • L. Zhao, E. Daly, G.K. Davis, G.V. Eremeev, A.V. Reilly, A-M. Valente-Feliciano, K.M. Wilson
    JLab, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts DE-AC05-06OR23177 and DE-AC02-76SF00515 for the LCLS-II Project.
Inter-cavity copper plated bellows are part of the LCLS-II cryomodule beamline components. Since the bellows are close to superconducting radio frequency (SRF) cavities during accelerator operation, it is desirable that these bellows have similar cleanliness as SRF cavi-ties. Studies have been done to help evaluate bellows interior cleanliness after the standard bellows cleaning procedure at Jefferson Lab.
 
poster icon Poster MOPO019 [1.326 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO019  
About • paper received ※ 28 August 2018      issue date ※ 18 January 2019  
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MOPO020 Beam Dynamics Studies and Instrumentation Tests for Bunch Length Measurements at CLEAR 74
MOOP08   use link to see paper's listing under its alternate paper code  
 
  • L. Garolfi, M. Bergamaschi, R. Corsini, A. Curcio, S. Döbert, W. Farabolini, D. Gamba, I. Gorgisyan
    CERN, Geneva, Switzerland
  • C. Bruni, P. Lepercq, H. Purwar, C. Vallerand
    LAL, Orsay, France
  • W. Farabolini
    CEA/DSM/IRFU, France
 
  A new CERN Linear Electron Accelerator for Research (named CLEAR) has been installed as a general-purpose user facility to study novel accelerating techniques, high-gradient structures, instrumentation and irradiation experiments. CLEAR is a flexible accelerator that can provide high quality bunched electron beams with a wide range of beam parameters up to an energy of 220 MeV, offering several testing capabilities. Among all the potential applications, novel accelerating techniques, such as plasma acceleration and THz generation are considered. These applications require shorter bunches, down to the 100 fs level. This paper reports on beam dynamics studies and instrumentation tests to establish a bunch length of this order in CLEAR. The short bunches are generated using adiabatic bunching in the first accelerating structure. For bunch length diagnostic CLEAR is equipped with a streak camera and a transverse deflecting cavity. Alternatively a phase-scan of the last accelerating structure could be used as well to estimate the bunch length. The experimental results with respect to these different techniques are presented and compared with simulations.  
slides icon Slides MOPO020 [0.864 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO020  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO024 Development of High Power Coherent Terahertz Wave Sources at Lebra 125 MeV Linac in Nihon University 78
 
  • T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, Y. Sumitomo, Y. Takahashi, T. Tanaka
    LEBRA, Funabashi, Japan
  • H. Ogawa, N. Sei
    AIST, Tsukuba, Ibaraki, Japan
 
  Funding: This work was supported by JSPS KAKENHI Grant Number JP16K17539 and JP16H03912.
Research and Development of a high performance electron linac for the generation of FEL, Parametric X-ray Radiation (PXR) and THz waves has been continued at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University as a joint research with KEK and National Institute of Advanced Industrial Science and Technology. The transport systems of the THz wave were installed in the vacuum chamber on the downstream side of the bending magnet of the PXR and FEL beam-line. The CER and the CSR are generated by the bending magnet each of the beam line. In addition, the CTR using thin metal foil is also generated. The average power of the CTR wave was measured approximately 1 mJ/macro-pulse (pulse width 4.5 µs) near the CTR wave beam source point in the frequency range of 0.1 - 2.5 THz. In addition, the energy of the CER as high as 0.2 mJ/macro-pulse were achieved with the experimental room. Furthermore, CER of the generated the FEL beam line can also be guided from the bending magnet on the downstream side of the undulator without disturbing the FEL oscillations. THz transport beam-lines and the characteristics of the THz waves are discussed in this report.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO024  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO026 The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac 81
 
  • M. Mohseni Kejani, F. Abbasi Davani
    Shahid Beheshti University, Tehran, Iran
  • S. Ahmadiannamin
    ILSF, Tehran, Iran
  • F. Ghasemi
    NSTRI, Tehran, Iran
  • S. Zarei
    Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
 
  A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO027 Photocathode Laser Pulse Shaping for Improved Emittance 84
 
  • M. Kotur, J. Andersson, J. Björklund Svensson, M. Brandin, F. Curbis, L. Isaksson, F. Lindau, R. Lindvall, E. Mansten, R. Svärd, S. Thorin, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  We present a setup for producing and characterizing picosecond ultraviolet laser pulses for use in the MAX IV photocathode electron gun preinjector. Frequency-tripled laser pulses from a commercial laser system are shaped directly in the ultraviolet domain using a Fourier-domain pulse shaper. The pulses were characterized using a transitent grating FROG. We discuss a proposed upgrade of the pulse shaper, as well as its limitations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO027  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO028 Survey and Alignment System of 100 MeV/100 kW Electron Linear Accelerator 87
SPWR006   use link to see paper's listing under its alternate paper code  
 
  • O. Bezditko, I.I. Karnaukhov, A.Y. Zelinsky
    NSC/KIPT, Kharkov, Ukraine
 
  For successful operation and working of electron linear accelerator of "NEUTRON SOURCE" driver it is necessary that all the acceleration sections, the quadrupole triplets, the quadrupole lenses, the dipole magnets, the scanning magnets and the chicane should be installed in design position according design parameters. Accuracies of all electromagnetic elements installation are 150 mkm for all three rotation freedom. The whole process, fiducialization and developing of survey net, alignment is controlled by laser tracker Leica AT 401.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO028  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO029 Physics design and dynamic simulation of a C-band photocathode electron gun for UEM 90
 
  • T. Chen, W. Li, Y.J. Pei, Zh. X. Tang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  For discovering structure at atomic scale and getting more details of chemical material and biological tissue, an ultrafast electron microscopy (UEM) has been developed and applied in plenty of subjects and studies. This paper described a C-band photocathode electron gun which will be working at 5712MHz to produce ultrashort electron beams with better dynamic parameters. The RF gun is using coaxial coupler to decrease the size of the gun and keep better symmetry of the field in the photocathode gun so that the beam emittance and energy spread can be reduce a lot. The photocathode rf gun will be a important part of the ultrafast electron microscopy (UEM). Using CST MWS and superfish code to simulate design the gun. After dynamic simulation, the beam parameters as the following: Energy is of 3MeV, Normal emittance of 0.12mm-mrad in boin direction, energy spread is of 5.8·10-4, which are better enough for an UEM.  
poster icon Poster MOPO029 [3.599 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO029  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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TU1P02
Interaction of electron beam with dielectric wakefield structure at TTX beamline  
 
  • D. Wang
    TUB, Beijing, People’s Republic of China
 
  Dielectric wakefield structure (DWS) find applications in many fields such as radiation source, wakefield acceleration, electron beam manipulations. Interaction of electron beam with dielectric wakefield structure is one of the hot topic. We have performed series of experiments on beam interaction with DWS at the TTX beamline, including experiment on the THz radiation, selectively excitation of THz by bunch train, and collinear wakefield acceleration with two beam interferometry method. This talk will give the details on the experimental results.  
slides icon Slides TU1P02 [3.338 MB]  
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WE1A06 Pulse-to-pulse Beam Modulation for 4 Storage Rings with 64 Pulsed Magnets 609
 
  • Y. Enomoto, K. Furukawa, T. Kamitani, F. Miyahara, T. Natsui, M. Satoh, K. Yokoyama, M. Yoshida
    KEK, Ibaraki, Japan
  • H.S. Saotome
    Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
  • S. Ushimoto
    Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
 
  The KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is planned to inject electron and positron beams with energies from 2.5 GeV to 7 GeV pulse-by-pulse at 50 Hz into the dual ring SuperKEKB collider and two light source storage rings. As the beam quality requirement from SuperKEKB is demanding, the beam orbit and optics conditions have to be maintained precisely. To that end 64 newly designed pulsed magnets were installed. Quadrupole magnets with the inductance of 1 mH are driven by power supplies with pulses up to 330 A and 0.5 ms, which recover the energy stored in coils up to 65%. Orbit corrector magnets with the inductance of 3 mH are driven with bipolar pulsed power supplies up to 10 A. Those power supplies are controlled under the event-based synchronized controls and monitored pulse-by-pulse, and are confirmed to have the stability over weeks within 0.1%. The details of the design and the operational performance will be reported.  
slides icon Slides WE1A06 [6.694 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A06  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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FR1A06 Pulse-by-Pulse Beam Parameter Switching of High-Quality Beams for Multi-Beamline Operation at SACLA 988
 
  • H. Maesaka, T. Fukui, T. Hara, Y. Otake
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • T. Hasegawa, O. Morimoto, Y. Tajiri, S. Tanaka, M. Yoshioka
    SES, Hyogo-pref., Japan
  • N. Hosoda, S. Matsubara, T. Ohshima
    JASRI/SPring-8, Hyogo-ken, Japan
  • C. Kondo, M. Yamaga
    JASRI, Hyogo, Japan
 
  The main linac of the X-ray free electron laser (XFEL), SACLA, provides electron beams to two XFEL beamlines and a beam transport line to the SPring-8 storage ring. In order to utilize these beamlines at the same time, a kicker magnet was installed into the switch yard and electron beams with a 60 Hz repetition rate can be distributed to these beamlines pulse-by-pulse. Since a beam energy and an optimum bunch length are usually different for each beamline, the operation condition of each acceleration unit, such as the rf phase, the trigger permission, etc., has to be changed pulse-by-pulse. Even in that case, the electron beam quality, such as 1 mm mrad normalized emittance, 10 fs bunch length, 10 kA peak current, etc., must not be deteriorated. At first, we developed a parameter control software that was able to manage two XFEL beamlines with an equal repetition rate. Different energy beams with sufficient quality for lasing were successfully distributed to the two XFEL beamlines and the XFEL performances of both beamlines were optimized simultaneously. The development status of a new parameter switching system with an arbitrary sequence of the destinations will also be reported.  
slides icon Slides FR1A06 [6.179 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A06  
About • paper received ※ 16 September 2018      issue date ※ 18 January 2019  
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