MOPO —  Monday Poster Session   (17-Sep-18   16:00—18:00)
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. Ghasemipresenter
    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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MOPO034 Dielectric Waveguide-Based THz Radiator Study for SwissFEL 94
MOOP06   use link to see paper's listing under its alternate paper code  
 
  • L. Shi, S. Bettoni, M.M. Dehler, E. Ferrari, B. Hermann, R. Ischebeck, F. Marcellini, S. Reiche, V.G. Thominet
    PSI, Villigen PSI, Switzerland
  • A.K. Mittelbach
    Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
 
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647
THz pulses have many unique properties in terms of radiation matter interaction. In particular their non-ionizing excitation of phonons in matter makes them a preferred pump for pump-probe studies at free electron lasers. In order to enrich the scientific potentials at SwissFEL (Swiss Free Electron Laser), which can provide ultrashort soft and hard X-ray pulses, we plan to build an economic THz radiator in the range of 1-20 THz by passing the spent electron beam through a dielectric lined tube after the electron beam has generated X-rays. These THz pulses will be transported to the photon user station. Since SwissFEL operates with 2 bunches, serving two beamlines, THz from the first bunch can be used at the user station of the second bunch to allow for pump arrival time before the probe. The core of such a THz generation setup is the dielectric lined tube and the relativistic electron beam. This paper reports on the numerical study of these tubes, in terms of mode structure, energy, pulse length etc, which are essential parameters for the pump-probe experiments. These tubes will be fabricated and tested in the near future in the electron beam line for the soft X-ray of SwissFEL.
 
slides icon Slides MOPO034 [1.471 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO034  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO035 Status of CLARA Front End Commissioning 98
MOOP03   use link to see paper's listing under its alternate paper code  
 
  • D. Angal-Kalinin, A.D. Brynespresenter, S.R. Buckley, P.A. Corlett, L.S. Cowie, K.D. Dumbell, D.J. Dunning, P.C. Hornickel, F. Jackson, J.K. Jones, J.W. McKenzie, B.L. Militsyn, A.J. Moss, T.C.Q. Noakes, M.D. Roper, D.J. Scott, B.J.A. Shepherd, E.W. Snedden, N. Thompson, C. Tollervey, D.A. Walsh, T.M. Weston, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R.J. Cash, R.F. Clarke, G. Cox, C. Hodgkinson, R.J. Smith, J.T.G. Wilson
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • K.D. Dumbell, B.J.A. Shepherd
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  CLARA (Compact Linear Accelerator for Research and Applications) is a Free Electron Laser (FEL) test facility under development at Daresbury Laboratory. The principal aim of CLARA is to test advanced FEL schemes which can later be implemented on existing and future short wavelength FELs. We report on the commissioning of the CLARA front end, consisting of a photoinjector and the first linac section, and merger into the existing VELA (Versatile Electron Linear Accelerator) beamline.  
slides icon Slides MOPO035 [1.870 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO035  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO036 Status of the 10 MW MBKs during Commissioning of the European XFEL in DESY 102
MOOP04   use link to see paper's listing under its alternate paper code  
 
  • V. Vogel (Fogel), Ł. Butkowski, A. Cherepenko, S. Choroba, J. Hartung
    DESY, Hamburg, Germany
 
  At present 26 RF stations for European XFEL are in operation. Each of the RF stations consists of a HV modulator located in a separate building on the DESY campus, up to 1600 m long 10 kV HV cables that connect the modulator and the HV pulse transformer located in the underground tunnel, 120kV, 3 m long HV cable connecting the HV pulse transformer and the connection module of the horizontal multi-beam klystron. Two RF stations of the injector have already achieved about 20000 hours of operation, RF stations of the XFEL bunch compressor area have operated up to 11000 hours and in the XFEL main linac up to 8000 hours. To increase the lifetime of the klystrons, we use a fast protection system (KLM) that is based on the comparison of the actual RF shape and the expected RF shape. In the case of a difference exceeding a certain margin, for example, in the case of RF breakdown in a klystron or RF breakdown in a waveguide system, the KLM quickly, shorter than 500 ns, switches off the input RF signal. Thus, it does prevents the vacuum level in the klystron worsen too much or it minimizes the RF overvoltage time at the output windows of the klystron in case of breakdown in waveguides.  
slides icon Slides MOPO036 [5.241 MB]  
poster icon Poster MOPO036 [0.658 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO036  
About • paper received ※ 05 September 2018      issue date ※ 18 January 2019  
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MOPO037 SRF Gun Development at DESY 105
MOOP07   use link to see paper's listing under its alternate paper code  
 
  • E. Vogel, S. Barbanotti, I. Hartl, K. Jensch, D. Klinke, D. Kostin, W.-D. Möller, M. Schmökel, J.K. Sekutowicz, S. Sievers, N. Steinhau-Kühl, A.A. Sulimov, J.H. Thie, H. Weise, L. Winkelmann, B. van der Horst
    DESY, Hamburg, Germany
  • J.A. Lorkiewicz, R. Nietubyć
    NCBJ, Świerk/Otwock, Poland
  • J. Smedley
    BNL, Upton, Long Island, New York, USA
  • J. Teichert
    HZDR, Dresden, Germany
  • M. Wiencek
    IFJ-PAN, Kraków, Poland
 
  A future upgrade of the European XFEL (E-XFEL) foresees an additional cw operation mode increasing the flexibility in the photon beam time structure. This mode requires among others a cw operating photo injector. We believe that using an SRF gun is the preferred approach as the beam parameters of normal conducting pulsed guns can be potentially met by SRF guns operating cw. Since more than a decade DESY in collaboration with TJNAF, NCBJ, BNL, HZB and HZDR performs R&D to develop an all superconducting RF gun with a lead cathode. In the frame of E-XFEL cw upgrade feasibility studies, the SRF-gun R&D program gained more attention and support. Within the next few years we would like to demonstrate the performance of the all superconducting injector required for the E-XFEL upgrade. The selected approach offers advantages w.r.t. the cleanliness of the superconducting surface, but requires a complete disassembly of a cryostat and stripping the gun cavity in a clean room to exchange the cathode. Thus it is practical only when the life time of the cathode is at least several months. In this paper we present the actual status of the R&D program, next steps and the longer term plans.  
slides icon Slides MOPO037 [1.966 MB]  
poster icon Poster MOPO037 [3.774 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO037  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO038 RF Operation Experience at the European XFEL 109
MOOP09   use link to see paper's listing under its alternate paper code  
 
  • J. Branlard, V. Ayvazyan, Ł. Butkowski, M.K. Grecki, M. Hierholzer, M.G. Hoffmann, M. Hoffmann, M. Killenberg, D. Kostin, T. Lamb, L. Lilje, U. Mavrič, M. Omet, S. Pfeiffer, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, V. Vogel, N. Walker
    DESY, Hamburg, Germany
 
  After its successful commissioning which took place during the first half of 2017, the European X-ray free electron laser is in now in regular operation delivering photons to users since September 2017. This paper presents an overview on the experience gathered during the first couple of years of operation. In particular, the focus is set on RF operation, maintenance activities, availability and typical failures. A first look on machine performance in terms of RF and beam stability, energy reach, radiation related investigations and microphonics studies will also be presented.  
slides icon Slides MOPO038 [2.421 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO038  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO039 Status Update of the Fast Energy Corrector Cavity at FLASH 112
 
  • S. Pfeiffer, J. Branlardpresenter, Ł. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella
    DESY, Hamburg, Germany
  • M. Fakhari
    CFEL, Hamburg, Germany
 
  Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.
 
poster icon Poster MOPO039 [1.884 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039  
About • paper received ※ 13 September 2018      issue date ※ 18 January 2019  
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MOPO040 Coherent Synchrotron Radiation Monitor for Microbunching Instability in XFEL 115
MOOP05   use link to see paper's listing under its alternate paper code  
SPWR002   use link to see paper's listing under its alternate paper code  
 
  • J.H. Ko, I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • H.-S. Kang, C. Kim, G. Kim
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  The microbunching instability is an important issue in an X-ray Free Electron Laser (XFEL). The intensity of the FEL can be reduced significantly by the microbunching instability so that the laser heater is widely used to reduce it. In the X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL), to directly monitor the microbunching instability, a visible CCD camera was included into the coherent radiation monitor (CRM) which uses a pyroelectric detector. It enabled us to measure the microbunching instability more clearly and optimize the FEL lasing in the PAL-XFEL.  
slides icon Slides MOPO040 [1.125 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO040  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO041 Performance Test Results of Magnet Power Supply 118
 
  • K.-H. Park, J.H. Han, S.-H. Jeong, Y.G. Jung, D.E. Kim, M.J. Kim, H.-G. Lee, S.B. Lee, B.G. Oh, H.S. Suh
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  A high stable magnet power supply (MPS) was developed, which was a bipolar type with 200A of the output current at the 40V of output voltage. The MPS has been implemented by the digital signal processing technology using the DSP, FPGA, ADCs and so on. The output current stability of the MPS showed about 6ppm peak-to-peak in a short term experiment at 200A of its full output current. The long term stability was shown in 15 ppm peak-to-peak for 10 hours at 200A. And the others experimental results about the MPS were shown in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO041  
About • paper received ※ 31 August 2018      issue date ※ 18 January 2019  
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MOPO042 Evolutionary Many-objective Optimization Algorithm for Large-bandwidth Free-Electron-Laser Generation 121
SPWR003   use link to see paper's listing under its alternate paper code  
 
  • J.W. Yan, H.X. Deng
    SINAP, Shanghai, People’s Republic of China
 
  Funding: National Natural Science Foundation of China , the National Key Research and Development Program of China, the Young Elite Scientist Sponsorship Program by CAST and Ten Thousand Talent Program.
X-ray free-electron lasers (XFELs) are leading-edge instruments in a wide range of research fields. Besides pursuing narrow bandwidth FEL pulses, the large-bandwidth XFEL pulses are very useful in various spectroscopy experiments, multi-wavelength anomalous diffraction, and X-ray crystallography. Overcompression operation scheme can be utilized to generate electron beams with large energy chirp which is benefit for bandwidth broadening. Recently, an evolutionary many-objective (having four or more objectives) algorithm, NSGA-III, was used to optimize the electron beam parameters in the overcompression including energy chirp, energy spread, current profile, peak current, and projected emittance. In this paper, combining with the Xie’s semianalytical estimate formula, the NSGA-III is utilized to find an optimal working point of linac by optimizing the XFEL pulse properties directly. Start-to-end numerical simulations based on the Shanghai soft X-ray Free-Electron Laser user facility parameters demonstrate that a full bandwidth of 4.75% can be generated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO042  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO053
Development of a Linear Electron Accelerator-based Neutron Source for Analysis of Structural Materials  
MOOP10   use link to see paper's listing under its alternate paper code  
 
  • B.E. O’Rourke, T. Fujiwara, K. Kino, R. Kuroda, K. Michishio, H. Ogawa, N. Oshima, D. Sato, N. Sei, R. Suzuki, M. Tanaka, H. Toyokawa, A. Watazu
    AIST, Tsukuba, Ibaraki, Japan
  • N. Hayashizaki
    RLNR, Tokyo, Japan
  • T. Muroga, T. Shishido
    ISMA, Ibaraki, Japan
 
  Funding: This paper is based on results obtained from Innovative Structural Materials R&D Project commissioned by the New Energy and Industrial Technology Development Organization(NEDO).
Neutrons are a powerful probe of structural materials due to their high penetration. As part of the Innovative Structural Materials R&D project funded by the New Energy and Industrial Technology Development Organization (NEDO), the Innovative Structural Materials Association (ISMA) is developing a dedicated, compact electron-accelerator based neutron source at the National Institute of Advanced Industrial Science and Technology (AIST) in Tsukuba, Japan, for the characterization of structural materials. The accelerator is designed to have a maximum electron beam power of 10 kW (~36 MeV and ~275 mA), which will be incident on a water-cooled Ta target. The electron beam will have a maximum pulse length of around 10 μs at a repetition rate of 100 Hz. Neutrons produced through photo-nuclear reactions will be cooled by a decoupled solid methane moderator. Using this pulsed, low-energy neutron beam we plan to perform various imaging spectroscopies of structural materials including Bragg-edge imaging. In this contribution we will describe the dedicated neutron source in more detail, with particular emphasis on the electron accelerator.
 
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MOPO058 Industrial Electron Linear Accelerator R&D in CIAE 124
 
  • J.H. Yang, Y. Yang, G. Yu, Z.Q. Zeng
    CIAE, Beijing, People’s Republic of China
  • Z.B. Zhu
    China Institute of Atomic Energy, Beijing, People’s Republic of China
 
  Electron linear accelerator(E-LINAC)is a vital accelerator type for accelerator applications, which widely applied in industry, agriculture and medical industry. The paper introduces R&D of industrial E-LINAC in China Institute of Atomic Energy (CIAE) , including electron gun, modulator, accelerating tube, assembling and testing. Based on these R&D results, the GT series for non-destructive testing(NDT) and FZ series for irradiation processing are developed successfully. At present these E-LINACs play important roles in pressure vessel inspection, food preservation, sterilization and material modification, promoting the E-LINACs application as well as economic development in China.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO058  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO059 Choke-Type Resonator for a Compact Storage Ring 126
 
  • L. Ovchinnikova, V.I. Shvedunov
    SINP MSU, Moscow, Russia
  • L. Ovchinnikova, V.I. Shvedunov
    LEA MSU, Moscow, Russia
  • A. Ryabov
    IHEP, Moscow Region, Russia
 
  We present the results of calculations and measurements the electrodynamic characteristics of the operating and high order modes of a choke-type resonator, intended for a 35-50 MeV storage ring, which is part of the Thomson X-ray generator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO059  
About • paper received ※ 09 September 2018      issue date ※ 18 January 2019  
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MOPO060 Linacs for Industry, Cargo Inspection and Medicine Designed by Moscow University 130
 
  • A.N. Ermakov, A.S. Alimov, A.N. Kamanin, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov
    SINP MSU, Moscow, Russia
  • A.S. Alimov, A.N. Ermakov, V.V. Khankin, L. Ovchinnikova, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, A.S. Simonov
    LEA MSU, Moscow, Russia
  • I.V. Shvedunov
    Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia
 
  Funding: Work supported in part by Ministry of Education and Science of Russia Grant # RFMEFI58217X0011
The report presents the results of development of applied linear electron accelerators with an energy of up to 10 MeV, performed by the Laboratory of Electron Accelerators MSU. We describe linear accelerators for mobile, stationary and train cargo inspection systems with interlaced energies and pulse repetition rate up to 2 kHz, accelerators for radiography, a sterilization accelerator with beam parameters that are adjustable over a wide range, and an accelerator for a radiotherapy complex.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO060  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO061 Beam Parameters Measurement of C-band 6 MeV Linear Electron Accelerator 133
 
  • D.S. Yurov, A.S. Alimov, A.N. Ermakov, V.V. Khankin, N.V. Shvedunov, V.I. Shvedunov
    SINP MSU, Moscow, Russia
  • L. Ovchinnikova
    Laboratory of Electron Accelerators MSU, Ltd, Physics Department, Lomonosov Moscow State University, Moscow, Russia
  • A.S. Simonov
    LEA MSU, Moscow, Russia
 
  The new linear electron accelerator with beam energy varied in the range of 2-6 MeV with dual-energy option has been designed by Laboratory of Electron Accelerators MSU Ltd. Linac is based on compact high gradient stand-ing wave C-band accelerating structure fed by multi-beam klystron and is used in the cargo inspection and cancer therapy complexes. In the report, we present the results of electron beam parameters measurements at special stand.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO061  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO062 Linear Electron Accelerator for Radiation Technologies with Beam Parameters Varied in a Wide Range 136
 
  • V.V. Khankin, A.S. Alimov, A.N. Ermakov, A.N. Kamanin, A. Kurilik, N.I. Pakhomov, N.V. Shvedunov, V.I. Shvedunov, D.S. Yurov
    SINP MSU, Moscow, Russia
  • A. Kurilik
    LEA MSU, Moscow, Russia
  • I.V. Shvedunov, A.S. Simonov
    Federal State Unitary Enterprise, Laboratory of Electron Accelerators MSU, Ltd, Moscow, Russia
 
  We present the overview and beam parameters measurements results as well as the operational experience with the S-band pulsed linear electron accelerator with beam energy in the range of 5-10 MeV and maximum beam power of up to 15 kW. The possibility of adjusting the beam parameters in a wide range, provided by the design and control system of the accelerator, allows to use the accelerator in a wide variety of radiation technologies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO062  
About • paper received ※ 07 September 2018      issue date ※ 18 January 2019  
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MOPO063 Development of Side-coupled X-band Medical Linear Accelerator for Radiotherapy 139
 
  • Y.S. Lee, Y.W. Choi, G.J. Kim, I.S. Kim, J.I. Kim, S. Kim, J.H. Lee
    KERI, Changwon, Republic of Korea
  • J.H. Hwang, Y.N. Kang, A.R. Kim, J.N. Kim, T.G. Oh, Y.A. Oh, Y. J. Seol, J.S. Shin
    The Catholic University of Korea, Seoul, Republic of Korea
 
  Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging devices such as CT or MRI, so that it is possible to precisely focus high dose radiation on tumor tissues while minimizing the normal tissue damage. In order to place the diagnostic and treatment devices simultaneously in a confined space, constraints related to interference and volume between the subsystems must be considered. To meet these requirements, the size and weight of the LINAC system need to be reduced, which can be achieved by applying X-band technology. For the purpose of use in IMRT based on image guided radiotherapy, we developed a 9.3 GHz X-band medical LINAC using side-coupled structure. The LINAC is designed to have the accelerating field strength of 16.8 MV/m, and the beam current transmission efficiency of 26 % at the end of accelerating cell when the supplied RF power is at 1.7 MW. Therefore, it can accelerate the electron beam up to 6.2 MeV with having about 90 mA beam current. We plan to carry out the performance test using beam diagnostics system and X-ray measurement system, and the details of design and experimental results of LINAC will be described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO063  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO064 O-Arm Mounted X-Band Linear Accelerator System for Radiotherapy 142
 
  • S. Kim, Y.W. Choi, G.J. Kim, I.S. Kim, J.I. Kim, J.H. Lee, Y.S. Lee
    KERI, Changwon, Republic of Korea
  • J.H. Hwang, Y.N. Kang, A.R. Kim, J.N. Kim, T.G. Oh, Y.A. Oh, Y. J. Seol, J.S. Shin
    The Catholic University of Korea, Seoul, Republic of Korea
 
  Current advances in radiotherapy are based on the precise imaging techniques, and there is a pressing need for the development of techniques that are capable of visualizing cancer tissues in real time in conjunction with radiotherapy. Indeed, the image-guided radiotherapy systems in which conventional diagnostic tools such as CT and MRI are combined with the linear accelerator (LINAC)-based radiotherapy have been extensively studied. In this work, we mounted 9.3GHz X-band LINAC designed by KERI on the 360 degree-rotatable O-arm system, which allows efficient integration of a diagnostic tool with a radiotherapy equipment. After mounting, the X-ray profile and percentage depth dose were measured by following the quality assurance using the AAPM TG-51,142 protocol. The beam profile symmetry was estimated to be 102.4% with ±3% tolerance. The X-ray dose was also measured by rotating the O-arm to confirm the stability of the mounted X-band LINAC. As a result, the standard deviation of the X-ray dose was shown to be 0.016 while rotating. Therefore, we demonstrate the feasibility of our O-arm X-band LINAC system for use in highly effective radiotherapy with simultaneous CT image guidance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO064  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO066 Simulation of the Transitional Process in Accelerating Sections by Equivalent Circuit Method 145
 
  • S.V. Matsievskiy, V.I. Kaminskiy, Ya.V. Shashkovpresenter
    MEPhI, Moscow, Russia
 
  Nowadays linac accelerating RF systems design is usually done by the finite difference method. It provides high accuracy of calculations and freedom in topology choosing, but may draw considerable amounts of computer resources with long calculation times. Alternative to this method, equivalent circuit method exists. The basic idea of this method is to build a lumped element circuit, which with certain approximation acts as an original accelerating cell. It drastically reduces the number of equations to solve. This method is long known but usually only used for the particular accelerating structures when speed of calculation is a key-factor. Present paper describes a way to numerically simulate transition processes in arbitrary coupled accelerating cells using the equivalent circuit method. This approach allows simulating transitional processes in accelerating structures significantly faster and allows doing so for structures with high quality factor and many cells - a hard task for conventional transient solvers based on the finite difference method.  
poster icon Poster MOPO066 [0.519 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO066  
About • paper received ※ 23 August 2018      issue date ※ 18 January 2019  
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MOPO069 Nuclear and Mechanical Basic Design of Target for Mo-99 Production Using High Power Electron Linac 148
 
  • A. Taghibi Khotbeh-Sara, F. Rahmani
    KNTU, Tehran, Iran
  • F. Ghasemipresenter
    NSTRI, Tehran, Iran
  • H. Khalafi
    AEOI, Tehran, Iran
  • M. Mohseni Kejani
    Shahid Beheshti University, Tehran, Iran
 
  Today providing enough supplies of 99mTc / 99Mo as a high usage radioisotope in diagnostic nuclear medicine for the world demand is a big challenge. One of the proofed ways to access reliable source of this radioisotopes is production using e-LINAC [1]. In this investigation it was tried to find the simple and the optimized design of 99Mo production target based on photoneutron reaction using e-LINAC. Based on the Monte-Carlo calculation for radiation transport and finite element thermal analysis, 9 thin plates of enriched 100Mo was suggested. Equal distance between plates was considered for cooling to prevent target melting. The main target includes only 100Mo in one-stage approach method to increase production rate in compare with two-stage approach [2]. Applying 2.5 m/s for inlet velocity of cooling water provides suitable cooling process with maximum temperature of target about 900 ˚C.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO069  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO070 Construction of the Side-coupled Standing-wave e-Linac 151
 
  • S. Zarei
    Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
  • F. Abbasi
    Shahid Beheshti University, Tehran, Iran
  • M. Bahrami, M. Lamehi
    IPM, Tehran, Iran
  • F. Ghasemipresenter
    NSTRI, Tehran, Iran
 
  Due to Iran’s growing need for accelerators in various applications, NSTRI electron linear accelerator project has been defined for medical and inspection applications. This accelerator is a 6 MeV side-coupled standing-wave that operate is π /2 mode in the frequency of 2998.5 MHz. In this paper the construction and measurement results of the tube of this accelerator are presented. The prototype tube was constructed from aluminum and was clamped with bolts. By using a network analyzer, electric and magnetic probes and a side-coupled cavity tuning method and a bead-pull measurement technique, RF measurements were carried out. The resonant frequency and quality factor have been achieved 2998.5 MHz and 7940 respectively .
low-energy accelerator, construction of linac, standing-wave linac
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO070  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO073 Coherent Edge Radiation Sources in Linac-Based Infrared Free-Electron Laser Facilities 154
 
  • N. Sei, H. Ogawa
    AIST, Tsukuba, Ibaraki, Japan
  • K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakaipresenter, Y. Sumitomo, T. Tanaka
    LEBRA, Funabashi, Japan
  • H. Ohgaki, H. Zen
    Kyoto University, Kyoto, Japan
 
  Funding: This study was financially supported by JSPS KAKENHI Grant Number JP16H03912.
National Institute of Advanced Industrial Science and Technology has been studied far-infrared coherent radiation at Linac-based infrared free-electron laser (FEL) facilities in col-laboration with Nihon University and Kyoto University. To obtain high FEL gain at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University and at Kyoto Uni-versity Free Electron Laser (KU-FEL), the electron-bunch length is compressed to less than 1 ps in their undulator sections. Short electron bunches are suitable for generating intense coher-ent radiation, and we have already developed some terahertz-wave sources based on the coher-ent synchrotron radiation and the coherent transition radiation [1-3]. However, it was difficult to observe them with sufficient intensity without disturbing the infrared FEL oscillations. Then, we now develop coherent edge radiation emitted from downstream bending magnets in the un-dulator sections. It can be extracted from the undulator sections without disturbing the FEL os-cillations. In this presentation, the observed coherent radiation at LEBRA and KU-FEL will be reported on.
[1] N. Sei et al., J. Phys. D: Appl. Phys. 46, (2013) 045104.
[2] N. Sei et al., Nucl. Instr. and Meth. A, 832, (2016) 208.
[3] N. Sei et al., Jpn. J. Appl. Phys.: 56, (2017) 032401.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO073  
About • paper received ※ 29 August 2018      issue date ※ 18 January 2019  
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MOPO076 Study on Generation of Variable Polarized Coherent THz Radiation Using a Crossed Undulator 157
SPWR004   use link to see paper's listing under its alternate paper code  
 
  • H. Saito, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, K. Takahashi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
 
  A variable polarized THz radiation source using a crossed undulator system has been developed at Tohoku University. In this scheme, two coherent undulator radiations from an extremely short electron bunch are used to control the polarization. They are linearly polarized radiations orthogonal to each other. Polarization of superimposed radiation is controlled by adjusting a relative phase between them. A compact planar undulator with seven periods has been designed for an experiment at our facility. The radiation frequency is 2.06 THz for electron beam energy of 22 MeV. The opening angle of the crossed undulator radiation was estimated to be 34 mrad (FWHM). Since the polarization state of the crossed undulator depends on observation angle, its angular dependence was evaluated. It was found that ideal polarization control is realized only in the angle range of 2.5 mrad, which is quite smaller than that of the radiation itself.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO076  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO077 Design of the High Gradient Negative Harmonic Structure for Compact Ion Therapy Linac 160
MOOP11   use link to see paper's listing under its alternate paper code  
 
  • S.V. Kutsaev, R.B. Agustsson, A.Yu. Smirnov, A. Verma
    RadiaBeam, Santa Monica, California, USA
  • A. Barcikowski, R.L. Fischer, B. Mustapha
    ANL, Argonne, Illinois, USA
 
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0015717 and Accelerator Stewardship Grant, Proposal No. 0000219678
A novel concept for an Advanced Compact Carbon Ion Linac (ACCIL) that will deliver up to 1 pnA of carbon ions with variable energy from 45 MeV/u to 450 MeV/u in a 45 m footprint, has been developed by Argonne National Laboratory (ANL) in collaboration with RadiaBeam. The ACCIL will have a 35 MV/m real-estate accelerating gradients that became possible to achieve with the development of novel S-band high-gradient structures, capable of providing 50 MV/m accelerating gradients for particles with β>0.3. In particular, a β=0.3 structure based on the novel approach of operation at the first negative spatial harmonic with the increased distance between the accelerating gaps will be presented. This is the first attempt to reach such high gradients at such small velocities. RadiaBeam and ANL have demonstrated the feasibility of building this structure for accelerating carbon ions by means of advanced computer simulations and are currently working towards the fabrication of this structure for high power tests.
 
slides icon Slides MOPO077 [1.863 MB]  
poster icon Poster MOPO077 [0.923 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO077  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO079 Cavity Design of a 7 MeV 325 MHz Proton APF IH-DTL for a Compact Injector 163
 
  • X. Li
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
  • X. Li, Y.H. Pu, X.C. Xie, M.H. Zhao
    SINAP, Shanghai, People’s Republic of China
  • F. Yang
    Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China
 
  Funding: National Key Research and Development Program of China (grant number 2016YFC0105408)
An Interdigit H-mode Drift-Tube-Linac (IH-DTL) with Alternating-Phase-Focusing (APF) method working at 325MHz was designed. With the RF field established properly in the cavity, protons can be accelerated from 3MeV to 7MeV successfully. In this paper, the process of designing such an APF IH-DTL cavity is going to be presented. Also, the characteristics of the cavity and pa-rameters studying of RF are going to be demonstrated.
 
poster icon Poster MOPO079 [0.433 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO079  
About • paper received ※ 02 September 2018      issue date ※ 18 January 2019  
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MOPO080 The Manufacturing of the CSNS DTL Tank 167
 
  • X.L. Wu, T. Luo
    CSNS, Guangdong Province, People’s Republic of China
  • L. Dong, K.Y. Gong, H.C. Liupresenter, H. Song
    IHEP, Beijing, People’s Republic of China
  • S.M. Liu
    DNSC, Dongguan, People’s Republic of China
 
  The DTL tank is a crucial component of the China Spallation Neutron Source (CSNS) linear accelerator (LINAC), which mainly use the technology of oxygen-free copper (OFC) electroplating on the inner surface of the 20# carbon steel tube. It is the first time to perform OFC electroplating with high electrical conductivity in the high intensity beam accelerator in China. In the process of cavity manufacturing, problems such as machining deformation, plating surface nodule and plating peeling are encountered. In this project, based on pre-research and information from literature, the formula of acid solution was improved to construct a stable pickling process protocol. The manufacturing process of DTL tank and the measurement details are introduced in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO080  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO081 Light Proton Therapy Linac LLRF System Development 171
 
  • B.B. Baricevic, A. Bardorfer, R. Cerne
    I-Tech, Solkan, Slovenia
  • G. De Michele, Ye. Ivanisenko
    AVO-ADAM, Meyrin, Switzerland
 
  Proton cancer therapy is a state-of-the-art medical treatment technique based on an accelerator beam production facility. The LIGHT linear accelerator design by AVO-ADAM offers a modular compact solution for precise control of the treatment dose delivery, both position and energy wise. Proton energy can be modulated at up to 200 Hz in a range from 70 to 230 MeV by varying the gradient of the accelerating structures. The normal conducting LINAC RF system is based on a 750 MHz RFQ and 12 S band stations individually controlled. A customized LLRF system is being developed on the Libera LLRF platform for the LIGHT project. The paper is describing the required cavity field control functionality and the other subsystems such as master oscillator reference, cavity tuning, real-time control, data acquisition, control system and synchronization interfaces.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO081  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO082 Commissioning Status of the Linac for the iBNCT Project 174
 
  • M. Sato, Z. Fang, M.K. Fukuda, Y. Fukui, K. Futatsukawa, Y. Honda, K. Ikegami, H. Kobayashi, C. Kubota, T. Kurihara, T. Miura, T. Miyajima, F. Naito, K. Nanmo, T. Obina, T. Shibata, T. Sugimura, A. Takagi, E. Takasaki
    KEK, Ibaraki, Japan
  • K. Hasegawa
    JAEA, Ibaraki-ken, Japan
  • H. Kumada, Y. Matsumoto, Su. Tanaka
    Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
  • N. Nagura, T. Ohba
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  • T. Onishi
    Tsukuba University, Ibaraki, Japan
  • T. Ouchi, H. Sakurayama
    ATOX, Ibaraki, Japan
 
  Boron neutron capture therapy (BNCT) is one of the particle-beam therapies which use secondary products from a neutron capture on boron medicaments implanted into cancer cells. This has been originally studied with neutrons from nuclear reactors, meanwhile, many activities have been recently projected with accelerator-based neutron generation. In the iBNCT (Ibaraki BNCT) project, the accelerator is consisted with a radio frequency quadrupole (RFQ) and an Alvarez type drift-tube linac (DTL). Protons extracted from an ion source are accelerated up to 3 MeV and 8 MeV, respectively, and bombarded onto a beryllium target to generate neutrons. The design of the linac is based on the J-PARC one, but the most significant difference is the higher duty factor to have a sufficient epithermal neutron flux for BNCT. We have started the commissioning from the end of 2016, and the beam current of 1.3 mA with a repetition of 50 Hz has been achieved with an acceptable stability. Further beam commissioning and reinforcement of the vacuum and cooling water system will be performed toward higher beam current. In this contribution, the current status and future prospects of the linac will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO082  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO084 The Simulation and Manufacture of the Room Temperature CH-DTL 177
 
  • J.H. Li, G. Han
    China Institute of Atomic Energy, Beijing, People’s Republic of China
  • C.G. Li
    CIAE, Beijing, People’s Republic of China
  • Z. Li
    SCU, Chengdu, People’s Republic of China
 
  The room temperature Cross-bar H Type Drift Tube Linac (CH-DTL) is one of the candidate acceleration structures working in CW mode. In order to optimize the parameters, the 3 dimensional electromagnetic field of the CH-DTL cavity is simulated. The method of parameter sweeping with constraint variable is better than the method of parameter sweeping with only one variable during the optimization. In order to simplify the manufacture, the drift tube surface can be designed as spherical shape. The CH-DTL cavity has been manufactured and tested.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO084  
About • paper received ※ 31 August 2018      issue date ※ 18 January 2019  
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MOPO085 Prototype of an Inter-digital H-mode Drift-tube Linac for Muon Linac 180
 
  • Y. Nakazawa, H. Iinuma
    Ibaraki University, Ibaraki, Japan
  • K. Hasegawa, Y. Kondopresenter, T. Morishita
    JAEA/J-PARC, Tokai-mura, Japan
  • N. Hayashizaki
    RLNR, Tokyo, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • Y. Iwata
    NIRS, Chiba-shi, Japan
  • N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
    KEK, Ibaraki, Japan
  • R. Kitamura, H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Sue
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
 
  An inter-digital H-mode (IH) drift-tube linac (DTL) is developed for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. A prototype with 6 cells of 0.45 m length was manufactured. The prototype accelerates muons from v/c = 0.08 to 0.15 stage. We conducted frequency measurement and bead-pull measurement as a low-power measurement, in order to evaluate the prototype product. In this paper, the results of the low-power measurement for prototype cavity will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO085  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO087 Cold Test of Hybrid RFQ Prototype 184
SPWR012   use link to see paper's listing under its alternate paper code  
 
  • P.Y. Yu, Y. He, C.X. Li, F.F. Wang, Z.J. Wang, B. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  Hybrid RFQ is proposed as a potential good choice at the low-energy range of linear accelerator, which is combined by four-vane RFQ structure and CH-DTL structure. It has higher energy gain rate compared to conventional RFQ, and it is more compact than traditional DTL. In order to research on process exploration and RF parameters of this structure, an aluminium prototype is developed. The cold test of Hybrid RFQ prototype is completed. This paper will present the results and analysis of the test.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO087  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO088 Study on a 325 MHz HOM Drift Tube Linac 187
 
  • L. Lu, T. He, W. Ma, C.C. Xing, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  Normally, drift tube linacs (DTL) are used following RFQ linacs for beam acceleration in middle and high beam energy region. but acceleration efficiency of DTLs is decreasing with beam energy increasing. Using resonated higher order mode (HOM) of cavity, DTL can get higher effective shunt impedance. we proposed a 325MHz DTL with TE115 mode. In this paper, the dynamics calculation and electromagnetic design of the HOM-DTL will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO088  
About • paper received ※ 13 September 2018      issue date ※ 18 January 2019  
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MOPO089 Design Details of the European Spallation Source Drift Tube LINAC 190
 
  • P. Mereu, M. Mezzano, C. Mingioni, M. Nenni
    INFN-Torino, Torino, Italy
  • G. Cibinetto
    INFN-Ferrara, Ferrara, Italy
  • F. Grespan, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
 
  The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper gives a detailed overview of the ESS-DTL current mechanical design, and the related driving criteria. It presents also an outlook of the main aspects of the assembly and installation, with related equipments, toolings and procedures.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO089  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO090 Measurements of the First Room Temperature CH Cavity for MYRRHA at IAP Frankfurt 193
 
  • K. Kümpel, S. Lamprecht, P. Müller, N.F. Petry, H. Podlechpresenter, S. Zimmermann
    IAP, Frankfurt am Main, Germany
 
  Funding: This work has been supported by MYRTE which is funded by the European Commission under Project-ID 662186.
The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is a planned accelerator driven system (ADS) for the transmutation of long-living radioactive waste. A critical passage for the beam quality and especially for the emittance is the injector, which for the MYRRHA project consists of a 4-Rod RFQ, two Quarter Wave Rebunchers (QWR) and a total of 16 normal conducting CH-DTL cavities. The first installment of the MYRRHA injector in Louvein-La-Neuve (Belgium) will include an ion source, a RFQ, the QWRs and the first seven CH DTL cavities. This paper will report on the status of the low level tests on CHs 1 and 2 as well as on further developments on CHs 8-15.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO090  
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MOPO092 A 3-gap Booster Cavity to Match Ion Source Potential to RFQ Acceptance 196
MOOP01   use link to see paper's listing under its alternate paper code  
 
  • R.E. Laxdal, Z.T. Ang, T. Au, S. Kiy, S.D. Rädel, O. Shelbaya, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
 
  The ISAC RFQ can accelerate ions with A/Q ration from 1 to 30 and requires an input energy of 2.04keV/u. The harsh environment of the ISAC on-line ISOL target facility makes it difficult to meet the energy for the heaviest masses. For these cases we have designed and installed a short three gap device that accelerates the beams produced at source potential to match the required energy for RFQ acceptance. The booster cavity operates at 11.7MHz, the RF frequency of the pre-buncher. The device can also be used as a second buncher to augment the acceptance in the RFQ or to improve the acceptance of higher space charge beams. The device will be described and the results of beam measurements will be given.  
slides icon Slides MOPO092 [7.627 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO092  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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MOPO093 A Study of a Cooling Configuration for an OFHC Copper Rebuncher 200
 
  • O. Mazor, M. Bukai, D. Nusbaum, J. Rodnizkipresenter
    Soreq NRC, Yavne, Israel
  • E. Dyunin
    Ariel University, Ariel, Israel
  • G. Ziskind
    Ben-Gurion University in the Negev, Beer Sheva, Israel
 
  Funding: Pazy Fund (Israel Atomic Energy commission) https://pazy.org.il
A four gap OFHC copper rebuncher is developed at SNRC as a research study and a risk reduction for the MEBT of SARAF Phase II proton/ deuteron linac. The rebuncher is designed to bunch a 5 mA CW beam at 176 MHz. The required cavity voltage according to beam dynamics evaluation is 150 kV with a beam aperture diameter of 40 mm at a beam energy of 1.3 MeV/u with a Q value of 8000. Considering utilizing this cavity for enhancing the beam energy, the cooling configuration is explored for a cavity voltage of 300 kV, consuming 20 kW dissipated power, at a peak electric field of 16 MV/m, equivalent to the Kilpatrick limit. The electro magnetic study conducted with the CST RF simulation package was reproduced at ANSYS HFSS. The simulated dissipated power along the rebuncher for 20 kW forward power injected through the coupler port with the HFSS driven model were assigned to the ANSYS Fluent model to explore the resulted temperature map. Several evolved cooling configurations were studied, including cooling of the drift tubes. In this configuration the temperature rise along the cavity is in the range of 30 K. A detailed design of the four gap rebuncher is following this study.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO093  
About • paper received ※ 03 September 2018      issue date ※ 18 January 2019  
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MOPO094 RF Stability Test of RFQ Cavity with Prototype Low-level Radio Frequency in RAON 204
 
  • D.Y. Lee, B.H. Choi, C.O. Choi, H. Jang, H.C. Jung, K.T. Son
    IBS, Daejeon, Republic of Korea
 
  RAON is a heavy ion accelerator of the Institute for Basic Sciences (IBS) in Korea. The prototype Low-Level Radio Frequency (LLRF) operated at 81.25 MHz has been designed and fabricated for a prototype Radio Fre-quency Quadrupole (RFQ) cavity in RAON. Stabilities of ±1 % in amplitude and ±1 degree in phase are required for specifications of the RFQ system. The prototype LLRF controls the RF amplitude and phase in the cavity by PID feedback loop. The prototype LLRF has been tested with one RFQ cavity and stabilities have been measured. In this paper, we present the design and results of stability test.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO094  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO095 A Risk Based Approach to Improving Beam Availability at an Accelerator Facility 207
MOOP12   use link to see paper's listing under its alternate paper code  
 
  • W.C. Barkley, M.J. Borden, R.W. Garnett, M.S. Gulley, E.L. Kerstiens, M. Pieck, D. Rees, F.E. Shelley, B.G. Smith
    LANL, Los Alamos, New Mexico, USA
 
  Funding: United States Department of Energy
This paper describes a risk-based approach to improving beam availability at an accelerator facility. Los Alamos Neutron Science Center (LANSCE), like many other accelerator facilities, was built many years ago and has been re-purposed when new missions were adopted. Many of the upgrades to the accelerator and beamlines allowed improvements in the general area of the upgrade but large-scale, system-wide improvements were never accomplished. Because of this, the facility operates with a mix of old and new equipment of varying condition. Limited budgets have constrained spending for spares procurement making it vital to prioritize those items predicted to have the highest impact to availability, should they fail. A systematic approach is described where equipment is inventoried, condition assessed, rated for potential failure and finally compiled into a risk-based priority list.
 
poster icon Poster MOPO095 [0.332 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO095  
About • paper received ※ 21 September 2018      issue date ※ 18 January 2019  
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MOPO096 Realistic Modeling of MEBT for the New LANSCE RFQ Injector 211
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
 
  The new RFQ-based proton injector at LANSCE requires a specialized medium-energy beam transfer (MEBT) after the RFQ at 750 keV due to a following long (~3 m) existing common transfer line that also transports H beams to the DTL entrance. The horizontal space for MEBT elements is limited because two beam lines merge at 18-degree angle. The MEBT includes two compact quarter-wave RF bunchers and four short quadrupoles with steerers, all within the length of about 1 m. The beam size in the MEBT is large, comparable to the beam-pipe aperture, hence non-linear 3D fields at large radii and field-overlap effects become important. With CST Studio codes, we calculate buncher RF fields and quadrupole and steerer magnetic fields, and use them for particle-in-cell beam dynamics modeling of MEBT with realistic beam distributions from the RFQ. Our results indicate significant emittance growth in MEBT not predicted by the standard beam dynamics codes. Its origin is traced mainly to the quadrupole edge fields; the buncher RF fields also contribute noticeably. Proposed design modifications improve the MEBT performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO096  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO100 Doubly Stripped Proton Causing Vacuum Leak at Brookhaven 200 MeV H linac Complex 214
 
  • D. Raparia, G. Atoian, T. Lehn, V. LoDestro, M. Mapes, A. McNerney, J. Ritter, A. Zelenski
    BNL, Upton, Long Island, New York, USA
 
  Doubly stripped H in the low energy beam transport are capture 180 degree apart in the RF of RFQ and accelerated to the full energies. These protons are bend in the opposite direction of H after the 200 MeV drift tube linac and caused vacuum leak. A new beam dump for these stripped protons is planned  
poster icon Poster MOPO100 [4.781 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO100  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO101 LINAC-multitool - an Open Source Java-toolkit 217
 
  • M. Schwarz, D. Bade, J. Corbet, H. Podlech
    IAP, Frankfurt am Main, Germany
 
  Funding: Work supported by BMBF contr. No. 05P15RFRBA and HIC for FAIR
Dedicating more precious time to advanced research instead of spending it towards timeconsuming routine tasks is a desirable goal in particle accelerator simulation and development. Requirements engineering was started at IAP in order to identify routine processes at our institute’s R&D that can be automated or simplified. Results indicated that there were several areas to consider: Bead pull measurements, data processing and visualization for the beam dynamics code LORASR, CST field map processing for the use with TraceWin, conversion between different particle distribution data formats and more. Subsequently development of the LINAC-Multitool started to rationalize these processes and replace preexisting scripts also to ensure consistency of results and increase transparency and reliability of computation. In order to guarantee maintainability, expandability and platform independence, LINAC-Multitool is programmed using Java and will be open source. This contribution presents the current state of development.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO101  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO102 Progress of MicroTCA.4 based LLRF System of TARLA 220
 
  • C. Gumus, M. Hierholzer, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • A.A. Aksoy, A. Aydin, Ç. Kaya
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  • O.F. Elcim
    Ankara University Institute of Accelerator Technologies, Golbasi, Turkey
 
  The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is constructing a 40 MeV Free Electron Laser with continuous wave RF operation. DESY is responsible for delivering a turnkey LLRF system based on MicroTCA.4 standard that will be used to control four superconducting (SC) TESLA type cavities as well as the two normal conducting buncher cavities. This highly modular system is further used to control the mechanical tuning of the SC cavities by control of piezo actuators and mechanical motor tuners. With the usage of ChimeraTK framework, integration to EPICS control system is also implemented. This poster describes the system setup and integration to the existing accelerator environment with hardware and software components along with the latest updates from the facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO102  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO104 LLRF R&D Towards CW Operation of the European XFEL 223
SPWR026   use link to see paper's listing under its alternate paper code  
 
  • A. Bellandi, V. Ayvazyan, J. Branlard, C. Gumus, S. Pfeiffer, K.P. Przygoda, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
 
  The ever growing request for machines with a higher average beam pulse rate and also with a relaxed (< 1 MHz) pulse separation calls for superconducting linacs that operate in Long Pulse (LP) or Continuous Wave (CW) mode. For this purpose the European X-ray Free Electron Laser (European XFEL) could be upgraded to add the ability to run in CW/LP mode. Cryo Module Test Bench (CMTB) is a facility used to perform tests on superconducting cavity cryomodules. Because of the interest in upgrading European XFEL to a CW machine, CMTB is now used to perform studies on XM-3, a 1.3 GHz European XFEL-like cryomodule with modified coupling that is able to run with very high quality factor (QL = 10E7…10E8) values. The RF power source allows running the cavities at gradients larger than 16 MV/m. Because of the QL and gradient values involved in these tests, detuning effects like mechanical resonances and microphonics became more challenging to regulate. The goal is then to determine the appropriate set of parameters for the LLRF control system to keep the error to be less than 0.01° in phase and 0.01% in amplitude.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO104  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO106 New Digital LLRF System for HIT 227
 
  • E. Feldmeier, Th. Haberer, A. Peters
    HIT, Heidelberg, Germany
 
  The Heidelberg Ion Therapy Center HIT is in clinical operation since 2009. The accelerator complex consists of a linear accelerator and a synchrotron to provide carbon ions and protons for clinical use as well as helium and oxygen ions. The analog LLRF system for the linac should be replaced after more than 10 years of continuous operation. In its life-time the LLRF caused no interruption of the clinical operation with a downtime of more than 15 minutes. In order to keep the reliability in the next 10 years at least as high, a new digital LLRF system is planned. Further difficulties for the installation of a new system are due to the clinical full time usage of the accelerator and the short maintenance slots of only two days in series.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO106  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO107 Performance Evaluation of the RF Reference Phase Stabilization System on Fiber-optical Link for KEK e/e+ Injector LINAC 230
SPWR027   use link to see paper's listing under its alternate paper code  
 
  • N. Liu, B. Du
    Sokendai - Hayama, Hayama, Japan
  • D.A. Arakawa, H. Katagiri, T. Matsumoto, S. Michizono, T. Miura, F. Qiu, Y. Yano
    KEK, Ibaraki, Japan
  • T. Matsumoto, T. Miura, F. Qiu
    Sokendai, Ibaraki, Japan
 
  KEK e/e+ injector is the 600 m J-shaped LINAC which has 8 RF sectors. Stabilization of RF phase reference for long distance transmission is necessary for stable RF operation. In the present system, single-mode fiber-optical links without feedback control are used from sector 2 to 5. For the SuperKEKB, the phase stability requirement is within 0.1 deg. rms. The more stable RF phase reference is necessary to improve the phase stability. In this paper, a feedback control system for RF reference phase stabilization is tested for system performance evaluation. The temperature and humidity characteristics of the electric and optical components and phase stabilized optical fiber (PSOF) with different wavelengths will also be presented.  
poster icon Poster MOPO107 [2.026 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO107  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO111 Development of New LLRF System at the J-PARC Linac 233
 
  • K. Futatsukawa, Z. Fang, Y. Fukui
    KEK, Ibaraki, Japan
  • Y. Sato
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  • S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
 
  In the J-PARC linac, the LLRF system with the digital feedback (DFB) and the digital feedforward (DFF) was adopted for satisfying requirement of amplitude and phase stabilities. It has been operated without serious problems. However, it has been used since the beginning of the J-PARC and more than ten years have already passed since the development. The increase of the failure frequency for this system is expected. Additionally, it is difficult to maintain it for some discontinued boards of DFB and DFF and the older developing environment of software. Therefore, we are starting to study the new LLRF system of the next generation. In the present, we are exploring several possibilities of a new way and investigating each advantage and disadvantage. The project and the status of the development for the new system in the J-PARC linac LLRF are introduced.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO111  
About • paper received ※ 22 September 2018      issue date ※ 18 January 2019  
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MOPO115 CEBAF Photo Gun RF System 236
 
  • T. E. Plawski, R. Bachimanchi, M. Diaz, H. Higgins, C. Hovater, C.I. Mounts, D.J. Seidman
    JLab, Newport News, Virgina, USA
 
  Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177 and DE-SC0005264.
During the CEBAF 12 GeV Upgrade at Jefferson Lab, a fourth experimental hall, ’D’, was added to the existing three halls. To produce four beams and deliver them to all halls concurrently requires new frequencies and a new timing pattern of the electron bunches. Since a photo-gun is used to produce electron bunches, the gun’s drive laser pulses need to be synchronized with the required bunch rate frequencies of 499 MHz or 249.5 MHz. To meet these new operational requirements, the new LLRF system has been proposed. Very specific requirements (dual frequency operation) on one side and the simple RF drive mode operation on the other imply the use of a commercial off-the-shelf digital platform rather than a system typical for RF cavity field control. We have chosen the Texas Instruments FPGA board along with a high-speed 8-Channel, 14-Bit board, and a 4-Channel, 16-Bit board. The DAC board includes the clock generator for clocking ADCs, DACs and the FPGA. The complete Gun Laser LLRF system has been designed, built, and recently commissioned in the CEBAF Injector. This paper will detail the design and report on commissioning activities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO115  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO116 Study on the Control Technology of Large-load Time Constant Accelerator Magnet Power Supply 239
 
  • X. Wang, F. Long
    IHEP, Beijing, People’s Republic of China
 
  With the increasing application of power supply to industrial system, digital control system has become the mainstream of modern industrial control system. The wide application of digital control system has also led to the rapid development of digital controller. In the field of accelerator magnet power supply, the adoption of digital closed-loop control has become a trend in recent years. Due to the system’s tracking and regulation characteristics, the output current will slowly track the change of the given value in the course of the given current gradually rising. When the system reaches steady state, the disturbance of the system requires the regulator to adjust at a faster rate to correct the impact of the disturbance on the system. Today’s digital power supply control method mainly reflected in when load time constant is large, interference or load change, the power output is prone to overshoot or adjust the time is long, so the tracking and adjustment features cannot be met simultaneously. Therefore, this paper will study the power supply digital control technology for large - load time constant and the independent control method of tracking and regulating.  
poster icon Poster MOPO116 [0.307 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO116  
About • paper received ※ 21 August 2018      issue date ※ 18 January 2019  
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MOPO118 Optimized Design for a Compact Linac with Collinear Absorbing Loads at the Hust FEL-THz 242
SPWR029   use link to see paper's listing under its alternate paper code  
 
  • J. Jiang, G. Feng, T. Hu, Y. Lu, X.D. Tu, Y.Q. Xiong
    HUST, Wuhan, People’s Republic of China
  • Y.J. Pei
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  To meet the requirement of miniaturization for high power THz radiation in the field of commercial and civil use, RF Linacs have been applied widely as beam injectors, and the Linac with collinear absorbing loads reveals the potential to achieve a tradeoff between performance and compactness. Under overall consideration of systematic conflicts, optimization choices for such Linacs involving power absorbing ability, accelerating efficiency, as well as beamline length were described in this context. Meanwhile, cold testing has been conducted to verify design parameters for the collinear absorbing loads. Furthermore, elaborated calculation of thermal power loss and integrated helical water channel cooling has been performed for the 14MeV Linac with collinear absorbing loads installed on the HUST FEL-THz, and online experiments demonstrated that both the accelerating efficiency and the water cooling performance fulfilled operation demands.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO118  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO119 Design of a Fully Automated Test Bench for Measuring the Field Distribution in Standing Wave Cavity 246
 
  • Y. Lu, G. Feng, T. Hu, J. Jiang, X.D. Tu, Y.Q. Xiong
    HUST, Wuhan, People’s Republic of China
 
  The resonant cavity plays a great role in the linear accelerator. An accurate measurement of the cavity field distribution is very important to design linear accelerators. A fully computer controlled bench for the electric field distribution has been developed in this context. Based on the perturbation theory, the acquisition of the resonant frequency shift is proportional to the square of E (electric field). In order to verify the reliability of the test bench, a standard cylindrical cavity has been tested in this measurement system. The simulation by HFSS (High Frequency Structure Simulator) and the practice will be both presented in this paper. And the result demonstrates that, because of its high concentricity, the automated test bench achieves high precision in measuring the distribution of electric field.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO119  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO120 Improvement of the Linear Part in the Tuner System of ADS 25 MeV Linac 250
 
  • L. Zhang, Z. Gao, L.B. Liu, F.F. Wang, B. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  Tuner system is the indispensable part of ADS high current proton superconducting linac. It influences the working frequency of superconducting cavity of particle accelerator. To completely understand the working situa-tion of the tuner system and analyses the problems existing in it, experiments of linear part were fully conducted.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO120  
About • paper received ※ 09 September 2018      issue date ※ 18 January 2019  
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MOPO121 Large-Scale Optical Synchronization System of the European XFEL 253
 
  • J.M. Müller, M. Felber, T. Kozak, T. Lamb, H. Schlarbpresenter, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
    DESY, Hamburg, Germany
 
  At the European XFEL, a facility-wide optical synchronization system providing a femtosecond-stable timing reference at more than 40 end-stations had been developed and installed. The system is based on an ultra-stable, low-noise laser oscillator, whose signals are distributed via actively length-stabilized optical fibers to the different locations across the accelerator and experimental areas. There, it is used to locally re-synchronize radio frequency signals, to precisely measure the arrival time of the electron beam for fast beam-based feedbacks, and to phase-lock optical laser systems for electron bunch generation, beam diagnostics and user pump-probe experiments with femtosecond temporal resolution. In this paper, we present the system’s architecture and discuss design choices to realize an extensible, large-scale synchronization infrastructure for accelerators that meets reliability, maintainability as well as the performance requirements. Furthermore, the latest performance result of an all-optically synchronized laser oscillator is shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO121  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO122 European XFEL Cooling and Ventilation Systems 257
 
  • J.-P. Jensen
    DESY, Hamburg, Germany
 
  The European Free Electron Laser XFEL is operating since 2016. The technical systems for cooling and Ventilation CV were design, built and commissioned by the DESY work package WP34. The CV systems will be described and presented. The water cooling system consists of 3 cooling systems: 30/45 °C LCW for klystron and magnet cooling, 20/30 °C LCW for tunnel rack cooling and 8/14 °C for air conditioning and dehumidification of the air. The ventilation of the tunnels is connected to a series ventilation system from the experimental hall in direction to the injector. The series ventilation of the tunnels saves costs for air treatment with cooling, heating and dehumidification. The tunnel walls are a good heat storage that increases the air temperature stability by a factor of ten. The advantages of this concept will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO122  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO124 Details of the Manufacturing Processes of the ESS-DTL Components 260
 
  • P. Mereu, F. Borotto Dalla Vecchia, C. Mingioni, M. Nenni, R. Panero
    INFN-Torino, Torino, Italy
  • A. Battistello, P. Bottin, D. Conventi, L. Ferrari, F. Grespan, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • A.G. Colombo
    INFN- Sez. di Padova, Padova, Italy
 
  The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper presents the details of the manufacturing processes with quality control reports of the components of the DTL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO124  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO125 Steering Magnets with Permanent Magnets 264
 
  • Y. Iwashita, M. Abe, T. Yako
    Kyoto ICR, Uji, Kyoto, Japan
  • Y. Fuwa
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • N. Terunuma
    KEK, Ibaraki, Japan
 
  Funding: This work was supported by the Collaborative Research Program of Institute for Chemical Research, Kyoto University (grant #2018-10)
Dipole magnet using permanent magnet technology is under investigation for correction magnets in beamline. It can reduce cost of electricity of coil excitation and cooling water pump, thick electric cabling and water piping, power supply, and their maintenance cost. The structure and the field adjustment scheme whith bipolar variable range will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO125  
About • paper received ※ 20 September 2018      issue date ※ 18 January 2019  
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MOPO127 Recent Results from MICE on Multiple Coulomb Scattering and Energy Loss 267
 
  • J.Y. Tang
    IHEP, Beijing, People’s Republic of China
  • J.C. Nugent
    University of Glasgow, Glasgow, United Kingdom
 
  Funding: STFC, DOE, NSF, INFN, CHIPP and more
Multiple Coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, available simulation codes (GEANT4, for example) are known to overestimate the scattering of muons in low Z materials. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in the fall of 2015 with the absorber vessel filled with xenon and in the spring of 2016 using a lithium hydride absorber. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are all compared with the Bethe-Bloch formula and with the predictions of various models, including the default GEANT4 model.
Submitted by the MICE speakers Bureau. If accepted a member of the collaboration will be selected for the mission
 
poster icon Poster MOPO127 [0.842 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO127  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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MOPO129 Recent Results from the Study of Emittance Evolution at MICE 270
 
  • W.B. Liu
    IHEP, Beijing, People’s Republic of China
  • V. Blackmore, C. Hunt
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
 
  Funding: STFC, DOE, NSF, INFN, CHIPP and more
The Muon Ionization Cooling Experiment (MICE) has measured the evolution of emittance due to ionization energy loss. Muons were focused onto an absorber using a large aperture solenoid. Lithium-hydride and liquid hy- drogen-absorbers have been studied. Diagnostic devices were placed upstream and downstream of the focus, ena- bling the phase-space coordinates of individual muons to be reconstructed. By observing the properties of ensem- bles of muons, the change in beam emittance was meas- ured. Data taken during 2016 and 2017 are currently un- der study to evaluate the change in emittance due to the absorber for muon beams with various initial emittance, momenta, and settings of the magnetic lattice. The current status and the most recent results of these analyses will be presented.
Submitted by the MICE speakers Bureau. If accepted a member of the collaboration will be selected for the mission
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO129  
About • paper received ※ 30 September 2018      issue date ※ 18 January 2019  
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MOPO130 Magnetic Flux Generated by Thermal Current in CEBAF 5-Cell Cavity System 273
 
  • R.L. Geng
    JLab, Newport News, Virginia, USA
  • S.C. Huangpresenter
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The unloaded quality factor Q0 of many 5-cell CEBAF cavities were lowered by a factor of ~2 from their vertical qualification testing to their beam operation in CEBAF tunnel. Causes of this Q0 degradation were studied previously, including a more recent one addressing static fluxes arising from magnetic components near a 5-cell cavity. This paper reports on a preliminary study of the dynamic fluxes generated by a thermal current. Such a thermal current arises from the Seebeck effect and flows in closed loops formed by a niobium cavity and its surrounding tuner rods and liquid helium vessel that are made of stainless-steel. The behaviors of magnetic fluxes in response to various thermal profiles on a 5-cell CEBAF cavity with integrated tuner rods were studied in a JLAB VTA dewar. An outcome of this study is a proposed cool-down procedure for eliminating the thermal current generated magnetic fluxes around 5-cell cavities placed in CEBAF tunnels. This procedure may be useful to improve cavity Q0 in a cost-effective manner, which in turn saves cryogenic expenditures for sustaining CEBAF operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO130  
About • paper received ※ 01 September 2018      issue date ※ 18 January 2019  
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MOPO132 The 7 MeV APF DTL for Proton Therapy 277
MOOP02   use link to see paper's listing under its alternate paper code  
 
  • X.C. Xie, D.M. Li, X. Li, Y.H. Pu, J. Qiao, M.H. Zhao, Z.T. Zhao
    SINAP, Shanghai, People’s Republic of China
  • Y.H. Pu, X.C. Xie, F. Yang
    Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People’s Republic of China
 
  Funding: This work is fund by Ministry of Science and Technology of the People’s Repulic of China, under Grant Number 2016YFC0105408
A 7MeV alternating phase focused (APF) drift tube linear (DTL) for proton therapy has been designed, and a design code has been developed based on a sinusoidal synchronous phase formula and a linearly increasing electrode voltage assumption. The design procedure includes the radio frequency quadrupole (RFQ) to drift tube linac (DTL) matching, and end-to-end simulation that conducted by Trace Win. Moreover, a cutting method has been performed to correct the integral electric field deviation of RF gaps.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO132  
About • paper received ※ 20 August 2018      issue date ※ 18 January 2019  
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