Keyword: operation
Paper Title Other Keywords Page
MO1P01 Status of the SNS Proton Power Upgrade Project target, linac, cryomodule, injection 24
 
  • J. Galambos, M.S. Champion, M.P. Howell, S.-H. Kim, J. Moss, M.A. Plum, B.W. Riemer, K.S. White
    ORNL, Oak Ridge, Tennessee, USA
  • M. S. Connell, R. W. Steffey
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  SNS plans to double the power capability of the SNS proton beam by increasing the beam energy and the beam current. Accelerator scope includes additional superconducting RF cryo-modules and supporting RF systems, and upgrades to existing RF systems. Also the accumulator storage ring and the neutron source target will be upgraded to accommodate the additional power. The technical approach, project status and plans will be discussed.  
slides icon Slides MO1P01 [6.457 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO1P01  
About • paper received ※ 10 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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MO1P02 Approaches to High Power Operation of J-PARC Accelerator linac, rfq, ion-source, cavity 29
 
  • H. Oguri
    JAEA/J-PARC, Tokai-mura, Japan
  
  Japan Proton Accelerator Research Complex (J-PARC) accelerators have been having over 10 years of operation experience. In 2006, the J-PARC linac started beam operation with an energy of 181 MeV. To realize the nominal performance of 1 MW at 3 GeV Rapid Cycling Synchrotron (RCS) and 0.75 MW at a 30 GeV Main Ring synchrotron (MR), the linac energy was upgrade to 400 MeV by adding an annular-ring coupled structure linac, and the beam current was also upgraded from 30 to 50 mA by replacing a new ion source and an RFQ. After the upgrade, the RCS demonstrated 1MW equivalent beam operation and currently operates 400 kW for the Material and Life Science Facility. The MR beam power is increasing and becomes about 480 kW beam to the Neutrino Facility and about 50 kW at the Hadron Experimental Facility. Further upgrade plan of 1.5 MW beam power from the RCS is now in consideration. To achieve the plan, it is necessary to increase by about 20 % both beam current and pulse length at the linac. The detail process in the past upgrade and the possibility for further upgrade at the linac will be presented in this talk.  
slides icon Slides MO1P02 [5.595 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO1P02  
About • paper received ※ 12 September 2018       paper accepted ※ 19 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 FEL, klystron, gun, cathode 102
 
  • V. Vogel (Fogel), L. 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       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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MOPO038 RF Operation Experience at the European XFEL cavity, FEL, MMI, LLRF 109
 
  • J. Branlard, V. Ayvazyan, L. 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO060 Linacs for Industry, Cargo Inspection and Medicine Designed by Moscow University electron, controls, klystron, radiation 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       paper accepted ※ 20 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 electron, radiation, controls, gun 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO064 O-Arm Mounted X-Band Linear Accelerator System for Radiotherapy linac, GUI, radiation, DSL 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO066 Simulation of the Transitional Process in Accelerating Sections by Equivalent Circuit Method coupling, simulation, MMI, interface 145
 
  • S.V. Matsievskiy, V.I. Kaminskiy, Ya.V. Shashkov
    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       paper accepted ※ 19 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 linac, proton, coupling, simulation 160
 
  • 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO082 Commissioning Status of the Linac for the iBNCT Project rfq, neutron, target, DTL 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO095 A Risk Based Approach to Improving Beam Availability at an Accelerator Facility experiment, GUI, factory, proton 207
 
  • 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       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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MOPO102 Progress of MicroTCA.4 based LLRF System of TARLA LLRF, controls, cavity, hardware 220
 
  • C. Gumus, M. Hierholzer, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • A.A. Aksoy, A. Aydin, C. 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO115 CEBAF Photo Gun RF System FPGA, laser, gun, LLRF 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       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO125 Steering Magnets with Permanent Magnets permanent-magnet, dipole, multipole, sextupole 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       paper accepted ※ 22 September 2018       issue date ※ 18 January 2019  
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MOPO130 Magnetic Flux Generated by Thermal Current in CEBAF 5-Cell Cavity System cavity, cryomodule, experiment, niobium 273
 
  • R.L. Geng
    JLab, Newport News, Virginia, USA
  • S.C. Huang
    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       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TU2A03 Layout of the New FAIR Post-stripper DTL for Intense Heavy Ion Beams DTL, quadrupole, cavity, emittance 303
 
  • S. Mickat, X. Du, P. Gerhard, L. Groening, M. Heilmann, M. Kaiser, A. Rubin, V. Srinivasan, W. Sturm
    GSI, Darmstadt, Germany
  
  The new post-stripper DTL at GSI shall accelerate uranium beams with space charge induced tune depressions of up to 37% to 11.4 MeV/u. Emittance dilution must be kept below few percent. However, the layout must also allow for delivery of lightest ions to just 3.0 MeV/u. This broad-banded range of requirements imposes huge challenges on the layout and fabrication especially of the cavities and drift tube magnets.  
slides icon Slides TU2A03 [4.777 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU2A03  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO014 TRIUMF ISAC LINAC Developments and Upgrades controls, ISAC, linac, TRIUMF 355
 
  • Z.T. Ang, T. Au, Y. Bylinskii, K. Fong, J.J. Keir, D. Lang, R.E. Laxdal, R. Leewe, B.S. Waraich, Z.Y. Yao, Q. Zheng, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
  
  TRIUMF ISAC accelerator complex is in consists of ISAC-I room temperature linac and ISAC-II superconducting linac structure. ISAC-I linac has seventeen RF systems in operation for about twenty years, and ISAC-II linac has forty superconducting QWR RF cavities in operation for more than ten years. A small ISAC booster 3-gap structure at 11.78 MHz located in upstream of RFQ has been designed and installed for energy matching to RFQ. A sliding mode extremum seeking control for LLRF control was developed and implemented in operation. Six of DTL systems have been working in the control mode. Two of them had been commissioning and in operation one and half year reliably. RFQ, two more DTL system, HEBT rebuncher and DSB buncher system will be upgraded in the sliding mode control soon. Twenty ISAC-II SBC superconducting cavity RF power amplifiers were upgraded from YV-229 triode tube amplifier into solid state amplifier(SSA). The prototype and four SSAs have been commissioned in 2017 and in operation successfully. The rest of 16 SSA have been tested in RF lab and installed for operation at the mid of this year.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO014  
About • paper received ※ 04 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TUPO029 Highlights of the XM-3 Cryomodule Tests at DESY cavity, cryomodule, FEL, feedback 388
 
  • J. Branlard, V. Ayvazyan, A. Bellandi, J. Eschke, C. Gumus, D. Kostin, K.P. Przygoda, H. Schlarb, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
  
  To investigate the feasibility of the continuous wave (cw) upgrade of the European XFEL (E-XFEL) DESY, on-going tests are performed on E-XFEL prototype and production cryomodules since 2011. For these studies, DESY’s Cryo-Module Test Bench (CMTB) has been equipped with a 105 kW cw operating IOT in addition to the 10MW pulsed klystron, making CMTB a very flexible test stand, enabling both cw and pulse operation. For these tests, E-XFEL-like LLRF electronics is used to stabilize amplitude and phase of the voltage Vector Sum (VS) of all 8 cavities of the cryomodule under test. The cryomodule most often tested is the pre-series XM-3, unique since it is housing one fine grain niobium and seven large grain niobium cavities. In autumn 2017, additional spacers were installed on all 8 input couplers to increase the maximum reachable loaded quality factor Ql beyond 2·107. With higher Ql, up to 6·107 for 6 cavities and 2.7·107 for 2 cavities, we have investigated the VS stability and SRF-performance of this cryomodule under various conditions of cooling down rate and operation temperature 1.65K, 1.8K and 2K, at gradients up to ca. 18MV/m. The results of these tests are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO029  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO032 First Test Results of Superconducting Twin Axis Cavity for ERL Applications cavity, HOM, SRF, linac 398
 
  • H. Park, S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • A. Hutton, F. Marhauser, H. Park
    JLab, Newport News, Virginia, USA
  
  Superconducting cavities with two beam pipes had been proposed in the past for energy recovery linac applications. The relatively complex geometry of those cavities presented a serious challenge for fabrication and surface processing. Main concerns have now been overcome with the production and successful RF testing of a new elliptical twin-axis cavity proposed by Jefferson Lab and optimized by the Center for Accelerator Science at Old Dominion University in the frame of a DoE accelerator stewardship program. The cavity design provides uniform accelerating or decelerating fields for both beams. This paper describes the cavity design, fabrication experience, and the first cold RF test results and explores potential applications especially for Jefferson Lab s EIC (JLEIC).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO032  
About • paper received ※ 20 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO043 New Progress with HF-free Chemical Finishing for Nb SRF Cavities cavity, SRF, niobium, controls 431
 
  • H. Tian, J. Carroll, C.E. Reece, B. Straka
    JLab, Newport News, Virginia, USA
  • T.D. Hall, M.E. Inman, R. Radhakrishnan, E.J. Taylor
    Faraday Technology, Inc., Clayton, Ohio, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Jefferson Lab has implemented a bipolar pulsed electropolishing system for final chemical processing of niobium SRF cavities. This FARADAYIC bi-polar electropolishing (BPEP) has been applied to single cells, a 7-cell CEBAF C100 cavity, and to 9-cell TESLA-style cavities.* As a mechanistic characterization of the process emerges, the critical role played by the local current density during each cathodic pulse is becoming clear. This influences system and operational parameter refinement. We present current process parameters, removal characterization, and rf performance of the processed cavities. This is the fruit of collaborative work between Jefferson Lab and Faraday Technology, Inc. directed toward the routine commercialization and industrialization of niobium cavity processing. We also present supporting data from controlled-parameter coupon studies
* E.J. Taylor, et al. "Electrochemical system and method for electropolishing superconductive radio frequency cavities" U.S. Pat. No. 9,006, 147 (& international counterparts) issued April 14, 2015. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO043  
About • paper received ※ 12 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TUPO055 Next Generation Nb3Sn SRF Cavities for Linear Accelerators cavity, SRF, linac, site 462
 
  • R.D. Porter, D.L. Hall, M. Liepe, J.T. Maniscalco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, P. Cueva, D.A. Muller, N. Sitaraman
    Cornell University, Ithaca, New York, USA
  
  Niobium-3 Tin (Nb3Sn) is a very promising alternative material for SRF accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (~ 96 MV/m) compared to conventional niobium. This material is formed by vaporizing Sn in a high temperature vacuum furnace and letting the Sn absorb into a Nb substrate to form a 2-3 um Nb3Sn layer. Current Nb3Sn cavities produced at Cornell achieve Q ~ 1010 at 4.2 K and 17 MV/m. Here we present a summary of the current performance of Nb3Sn cavities at Cornell and recent progress in improving the accelerating gradient.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO055  
About • paper received ※ 20 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO069 Development of Vertical Electropolishing Facility for Nb 9-cell Cavity (2) cavity, controls, cathode, niobium 494
 
  • Y.I. Ida, V. Chouhan, K.N. Nii
    MGH, Hyogo-ken, Japan
  • T. Akabori, G.M. Mitoya, K. Miyano
    HKK, Morioka, Japan
  • Y. Anetai, F. Takahashi
    WING. Co.Ltd, Iwate-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  
  In IPAC18 (Vancouver, Canada), we reported our first step of development of niobium 9-cell cavity vertical electropolishing (VEP) facility. In this article, we will report the method, system for uniform polishing for niobium 9-cell cavities and the current situation of our 9-cell cavity VEP facility (The result of polishing uniformity, vertical test will be presented in other posters of this conference). In addition, we will show the movie of experiments of VEP-3 with Ninja cathode. This facility aims not only for test VEP but also for mass production and long-time operation.  
poster icon Poster TUPO069 [0.316 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO069  
About • paper received ※ 13 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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TUPO070 Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development cavity, vacuum, injection, MMI 496
 
  • K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai
    KEK, Ibaraki, Japan
  
  Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070  
About • paper received ※ 19 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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TUPO130 The Design of HEPS Magnet Database and Applications database, magnet-design, software, controls 591
 
  • Y.S. Qiao, F.S. Chen, C.P. Chu
    IHEP, Beijing, People’s Republic of China
  
  HEPS (High Energy Photon Source) is a planned ultra-bright and extremely low emittance synchrotron light source which will contain about 2500 magnets. The magnet related data including design, measurements, tests, and operation are typically scattered in various storages which can be hard to access for high-level purposes. For such a large number of magnets, it is very important to have essential magnet information systematically stored in relational databases for efficient management and applications. This paper outlines the conceptual and the functional design for the HEPS magnet database and its associated applications, mainly for design of the database schema and application software architecture. This database is developed with MySQL. To provide a better view and access function of magnet related data, a web-based management platform has been developed for data uploading, querying and data managing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO130  
About • paper received ※ 10 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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WE1A05 SwissFEL Linac Commissioning Status, Current Performance and Future Plans linac, FEL, electron, experiment 605
 
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  
  SwissFEL, the hard x-ray free-electron laser facility at PSI, is in an advanced commissioning phase. The commissioning of the 5.8 GeV Linac started in 2016 and the first FEL pilot-experiments were performed at a reduced beam energy in the end of 2017. In 2018, it is foreseen to progressively increase the electron beam energy and photon energy up to the maximum design values, interleaved by several FEL pilot experiments. This paper gives an overview of the commissioning progress including the achieved machine performance and first operational experience.  
slides icon Slides WE1A05 [10.370 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A05  
About • paper received ※ 18 September 2018       paper accepted ※ 09 October 2018       issue date ※ 18 January 2019  
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WE2A04 Commissioning of New SARAF RFQ and Design of New Linac rfq, linac, proton, emittance 626
 
  • A. Perry, D. Berkovits, H. Dafna, B. Kaizer, J. Luner, J. Rodnizki, A. Shor, I. Silverman, L. Weissman
    Soreq NRC, Yavne, Israel
  • A. Bechtold, P. Niewieczerzal
    NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
  • R.D. Duperrier, G. Ferrand, B. Gastineau, M. Jacquemet, C. Madec, N. Pichoff, D. Uriot
    CEA/IRFU, Gif-sur-Yvette, France
  • S. Ladegaillerie, Th. Plaisant
    IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France
  
  Status of the CEA desing of the future Saraf linac (title to be revised)  
slides icon Slides WE2A04 [7.096 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A04  
About • paper received ※ 17 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TH2A01 Nitrogen Infusion R&D for CW Operation at DESY cavity, FEL, SRF, niobium 652
 
  • M. Wenskat, A.D. Dangwal Pandey, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise
    DESY, Hamburg, Germany
  • C. Bate, G.D.L. Semione, A. Stierle
    University of Hamburg, Hamburg, Germany
  • B. Foster
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • B. Foster
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  The European XFEL cw upgrade requires cavities with reduced surface resistance (high Q-values) for high duty-cycle while maintaining high accelerating gradient for short-pulse operation. To improve on European XFEL performance, a recently discovered treatment is investigated: The so called Nitrogen-infusion. The recent test results of the cavity based R&D and the progress of the relevant infrastructure is presented. The aim of this approach is to establish a stable, reproducible recipe and to identify all key parameters for this process. In parallel, advanced surface analyses, such as SEM/EDX, TEM, XPS, XRR, GIXRD and TOF-SIMS, of samples after in-situ treatment, cut-outs of cavities and samples treated together with cavities are done. The aim of this approach is to understand the underlying processes of the material evolution, resulting in the improved performance. Results of these analyses, their implications for the cavity R&D, and next steps are presented.  
slides icon Slides TH2A01 [4.597 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH2A01  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO008 Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK cavity, linac, vacuum, cryomodule 695
 
  • H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori
    KEK, Ibaraki, Japan
  
  We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO011 First Energy Recovery Operation at the S-DALINAC: RF Control Stability Measurements controls, cavity, linac, beam-loading 706
 
  • M. Steinhorst, M. Arnold, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • C. Burandt
    HIM, Mainz, Germany
  
  Funding: *Supported by the DFG through GRK 2128.
One of the main research instruments at the institute for nuclear physics at the TU Darmstadt is the recirculating superconducting linear accelerator S‑DALINAC. Many improvements were implemented since the first recirculated beam in 1991. One of the major enhancement is the upgrade from a twice to a thrice recirculating scheme in 2015/2016. With this upgrade the operation mode can be changed between a conventional accelerating operation and energy recovery linac (ERL) mode by an 180° rf phaseshift of the beam done via a path length variation of the arcs in the second recirculation. ERL operation was not possible when the rf control system for the superconducting structures was set up in 2010. Therefore the current rf control system is not optimized for this kind of operation and so it had to be tested during ERL operation in order to also demonstrate its capability of this operation mode. In August 2017 a first once recirculating ERL operation was achieved. During this operation measurements regarding the rf control stability and the demand of rf power were done. This contribution is discussing this measurements and possible improvements for future energy recovery beam times. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO011  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO012 Once Recirculating Energy Recovery Linac Operation of S-DALINAC* linac, simulation, acceleration, recirculation 710
 
  • M. Arnold, J. Birkhan, J. Pforr, N. Pietralla, F. Schließmann, M. Steinhorst
    TU Darmstadt, Darmstadt, Germany
  • F. Hug
    KPH, Mainz, Germany
  
  Funding: *Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
Since 1991 the superconducting S-DALINAC is running in recirculating operation. It was built in a twice recirculating layout. A third recirculation beam line was added in 2015/2016 as an upgrade. The new recirculation beam line is installed in-between the two existing beam lines. It houses a path length adjustment system capable of changing the length of the orbit for recirculation by up to 10 cm corresponding to the RF wave length at the operation frequency of 3 GHz and consequently to a freedom of RF phase adjustment by 360°. The new beam line can, thus, be utilized for an accelerating operation or, if the change in phase is set to 180°, for an energy recovery linac (ERL) operation. In August 2017 the S-DALINAC was first operated in once recirculating ERL mode and became the first running ERL in Germany. Different aspects of this ERL run have been observed and were evaluated. The layout of the S-DALINAC allows a once or twice recirculating ERL mode. Beam dynamics simulations for both modes have been conducted or are currently under investigation. This contribution will discuss the once recirculating ERL operation, its results, and future plans concerning ERL measurements. 		 
poster icon Poster THPO012 [0.708 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO012  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO026 The Multi-physics Analysis of Dual-beam Drift Tube Linac DTL, cavity, simulation, linac 735
 
  • T. He, L. Lu, W. Ma, L.P. Sun, C.C. Xing, X.B. Xu, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The DB-DTL prototype is proposed to validate the fea-sibility of multi-beam accelerator in middle energy region. The main parameters are listed in Table.1. The DB-DTL will operate as pulse injector with the capacity of accelerating proton from 0.56 MeV to 2.5 MeV. The 35.83 kW normalized power dissipation of DB-DTL dis-sipated on the cavity internal surface will heat the cavity and cause cavity temperature rise and structural defor-mation, which will lead to resonant frequency shifting. The cooling water takes away the power to resolve this problem. In this paper, detailed multi-physics field simu-lation of DB-DTL is performed by using ANSYS multi-physics, which is a coupled electromagnetic, thermal and structural analysis.  
poster icon Poster THPO026 [0.759 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO026  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO029 Quality Factor and Power Loss of the CSNS DTL cavity, DTL, simulation, linac 741
 
  • P.H. Qu, M.X. Fan, A.H. Li, B. Li, J. Peng, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liu
    IHEP, Beijing, People’s Republic of China
  
  An Alvarez-type Drift tube linac (DTL) was utilized to accelerate the H− ion beam of up to 15mA peak current from 3 to 80MeV of China Spallation neutron source (CSNS). For ease of manufacturing and measurement, the CSNS DTL was divided into four independent cavities. The Q factor of four cavities were given, including the measurement results of low-power[1] and high-power[2], and several reasons for the low Q factor of the cavity in the measurement process were analysed. During the op-eration of the DTL, the frequent alarm of the water flow switch causes the power of the cavity to fall to 0. Esti-mate the power loss of each component, under the cir-cumstances of ensuring adequate water flow, reduce the alarm threshold of the water flow switch of some compo-nents to improve the stability of the system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO029  
About • paper received ※ 22 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO030 Operation Experience of the CSNS DTL DTL, MMI, linac, vacuum 744
 
  • H.C. Liu, Q. Chen, S. Fu, K.Y. Gong
    IHEP, Beijing, People’s Republic of China
  • M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  
  The China Spallation Neutron Source (CSNS) Drift tube linac (DTL) accelerates H− beam from 3 to 80MeV with 4 independent tanks. The 80MeV beam acceleration was achieved in January 2018. The linac is a key to the reliability of the whole CSNS facility since all the beams stop when these upstream facilities fail. Many efforts have been made for DTL reliable operation. This paper presents the operation experience learned in DTL com-missioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO030  
About • paper received ※ 28 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO031 RF Conditioning and Beam Commissioning Status of CSNS DTL DTL, cavity, vacuum, MMI 747
 
  • Y. Wang, M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liu
    IHEP, Beijing, People’s Republic of China
  
  The high power RF conditioning of CSNS DTL was finished in April 2017 with peak input power 1.6MW, 650us pulse width, 25Hz repetition frequency. With careful tuning of RF amplitude and phase, beam was accelerated to 80MeV successfully with maximum peak beam current 12mA and about 98% transmission efficiency. DTL operate stably at full power level with several trips per day without beam interruption after six months commissioning. The whole RF conditioning process was presented and some details of beam commissioning were described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO031  
About • paper received ※ 05 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO038 Status of the Power Couplers for the CSNS DTL DTL, coupling, cavity, vacuum 767
 
  • M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liu
    IHEP, Beijing, People’s Republic of China
  
  There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented.
This work was supported by Youth Innovation Promotion Association of CAS (2015011) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038  
About • paper received ※ 30 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO039 The Status of CSNS Front End rfq, ion-source, emittance, MMI 771
 
  • H. Li, X. Cao, W. Chen, T. Huang, S. Liu, K. Xue
    CSNS, Guangdong Province, People’s Republic of China
  • S. Fu, Y.J. Lv, H.F. Ouyang, Y.C. Xiao
    IHEP, Beijing, People’s Republic of China
  
  CSNS front end is currently under running, which consists of a H− penning ion source(IS), a low energy beam transport(LEBT), a radio frequency quadrupole (RFQ) and a medium energy beam transport(MEBT). CSNS ion source is a type of Penning surface plasma source, similar to ISIS ion source. Cesium is used to enhance the H− ion production efficiency. The ion source is running with duty factor of 1.25%(25Hz and 500us). Normally, 40mA H− beam from ion source with 50keV can be delivered into LEBT. Three solenoids and two direction magnets are employed to transport and match the beam from the ion source into the RFQ. The pre-chopper is installed at the end of LEBT. The chopper mainly works at 3.8-4.2 kV and 1 MHz rate, which is about the RF frequency of the ring at injection. The rise time is less than 10ns，which fulfills the requirement of ring injection. For the RFQ, it is a 324MHz 4-vane type with a output energy of 3.0MeV and the length of 3.62m. The input cavity power is about 400kW. During commissioning, 16mA H− beam can be obtained at the exit of RFQ, and the RFQ transmission rate is up to 94%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO039  
About • paper received ※ 03 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO040 Operation Experiences of the J-PARC Linac linac, DTL, cavity, target 774
 
  • K. Hasegawa
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The J-PARC linac has delivered beam to users since 2008. As of 2018, the linac provides a 40 mA beam at an energy of 400 MeV to the following Rapid Cycling Synchrotron. We have had many issues to impede high availability during the operation. One of them was troubles of high voltage power supply of klystrons. The other category is related to vacuum property in accelerating cavities. The vacuum pumps were reinforced at the RFQ#1 in 2009. The cleaning of the inside surface of some acceleration cavities were performed after the big earthquake in 2011. The cooling water flow rate drop had been a long-time issue. We modified a cooling system to take better flow balances. As a result of these improvement, the availability is approximately 92% or more in these days. However, we have encountered another issue due to some aging components. The operation experiences and availability improvement at the J-PARC linac will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040  
About • paper received ※ 19 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO052 High Power Test of the LEAF-RFQ rfq, acceleration, quadrupole, cavity 808
 
  • L. Lu, Y. He, W. Ma, L.B. Shi, L.T. Sun, L.P. Sun, L. Yang, Y. Yang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  High power heavy ion drivers require a CW low-frequency accelerator for initial acceleration. A CW four-vane radio frequency quadrupole (RFQ) accelerator is designed to accelerate heavy ions A/q up to 7 from 14 keV/u to 500 keV/u, as a new injector for the Low Energy Accelerator Facility (LEAF) at Institute of Modern Physics (IMP). The measurements of low power test were reported previously. In this paper, the results of high power test of the RFQ, including the test of the acceleration systems and beam profiles, will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO052  
About • paper received ※ 07 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO062 IFMIF/EVEDA RFQ Preliminary Beam Characterization rfq, MMI, simulation, proton 834
 
  • E. Fagotti, L. Antoniazzi, L. Bellan, M. Comunian, F. Grespan, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo
    INFN/LNL, Legnaro (PD), Italy
  • T. Akagi, K. Kondo, K. Sakamoto, T. Shinya, M. Sugimoto
    QST, Aomori, Japan
  • P. Cara
    IFMIF/EVEDA, Rokkasho, Japan
  • H. Dzitko, I.M. Moya
    F4E, Germany
  • R. Heidinger, A. Marqueta
    Fusion for Energy, Garching, Germany
  • I. Podadera
    CIEMAT, Madrid, Spain
  
  The IFMIF/EVEDA RFQ is the longest and powerful operated. Therefore, it requires a careful characterization from several aspects: beam dynamics, RF, mechanics, installation and commissioning. Due to the very large power handling, the preliminary beam operation was decided to be performed with a low proton beam current at one half of the voltage needed for deuteron accelera-tion, i.e. from 8 mA to 30 mA at 2.5 MeV in pulsed mode, with respect to the nominal 130-mA deuteron beam at 5 MeV in CW. In this framework, it will be presented the characterization of the RFQ in terms of simulation and measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO062  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO079 RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations cavity, diagnostics, emittance, electron 866
 
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  • K. Flöttmann
    DESY, Hamburg, Germany
  
  For diagnostic of longitudinal distribution of electrons in unique REGAE bunches is applied a specially developed deflecting structure with minimized level of aberrations in the field distribution and improved RF efficiency. Short deflecting cavity was constructed and installed now in REGAE beam line. The cavity is tested at operational level of RF power. The main distinctive features of the cavity are mentioned and obtained results are reported.  
slides icon Slides THPO079 [1.803 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO092 LCLSII Fundamental Power Coupler Manufacturing Status and Lesson Learned FEL, factory, SRF, status 893
 
  • S. Sierra, G. Garcin, Ch.L. Lievin, G. Vignette, I. Yao Leclerc
    TED, Velizy-Villacoublay, France
  • M. Knaak, M. Pekeler
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  
  Thales and RI Research Instrument have manufactured and assembled half of the power couplers for the LCLSII project. This paper remains main characteristics of these coupler. It will also describe main challenges that were overcome among them, thickness of copper coating on Warm Internal Conductor at 150µm and lessons learned during the manufacturing phase of these couplers. The paper will also propose some possible optimization for a future mass production of such components and parameters which could be relevant for a better understanding link to the statistic results obtained.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO092  
About • paper received ※ 10 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO102 Design Studies of Output Window for CEPC Klystron klystron, multipactoring, simulation, electron 911
 
  • Z.J. Lu, Y.L. Chi, S. Fukuda, G. Pei, S. Pei, S.C. Wang, O. Xiao, U. N. Zaib, Z.S. Zhou
    IHEP, Beijing, People’s Republic of China
  • S. Fukuda
    KEK, Ibaraki, Japan
  
  A high power and high efficiency klystron of the 650MHz, 800kW CW klystron for the Circular Electron Positron Collider (CEPC) is designed and developed at IHEP. This paper presents the design and simulation for the high power coaxial window for it. Plan of the hot test (high power testing before installing to the klystron) are also described. Simulation software of CST, ANSYS and Multipac 2.1 are used for design of window microwave structure, thermal analysis and multipacting effects. We obtained the good simulation results successively; the coaxial window S-parameter analysis, has revealed a low reflection at the operating frequency of 650 MHz. The thermal simulation shows a good temperature distribution under the cw 800kW propagation; maximum temperature has been found to be 33 °C at ceramic with water cooling in the inner and outer conductor. The multipacting at the window is possible source of the failure and it is shown that multipacting has less chance to be happened on the surface of ceramic.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO102  
About • paper received ※ 12 September 2018       paper accepted ※ 31 October 2018       issue date ※ 18 January 2019  
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THPO125 Runing Status of SRF Gun II at the ELBE Radiation Center gun, SRF, cathode, laser 952
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J.S. Schaber, J. Teichert, H. Vennekate, P.Z. Zwartek
    HZDR, Dresden, Germany
  
  Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1 and the Deutsche Forschungsgemeinschaft (DFG) grant XI106/2-1.
As a new electron source with higher brilliance, the second version of the superconducting RF photoinjector (SRF Gun II) has been successfully commissioned at the ELBE Center for High-Power Radiation Sources since 2014. SRF Gun II features an improved 3.5-cell niobium cavity as well as a superconducting solenoid in the same cryomodule. For user operation the SRF Gun II with Mg photocathode successfully generated stable beam with bunch charges up to 200 pC in CW mode, and with sub-ps bunch length. In this presentation the gun’s status and beam parameters will be presented. 		 
poster icon Poster THPO125 [1.520 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO125  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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FR1A05 Development of Pulsed Gas Strippers for Intense Beams of Heavy and Intermediate Mass Ions target, heavy-ion, injection, linac 982
 
  • P. Gerhard, W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, M.T. Maier, P. Scharrer, A. Yakushev
    GSI, Darmstadt, Germany
  • W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar
    HIM, Mainz, Germany
  • Ch.E. Düllmann
    Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany
  
  The GSI UNILAC together with SIS18 will serve as injector for the future FAIR. A modified 1.4~MeV/u gas stripper setup has been developed, aiming at an increased yield into the particular desired charge state. The setup delivers short pulses of high gas density in synchronization with the beam pulse. This provides a higher gas density. Different gases as stripping targets were tested. Measurements with various isotopes and gas densities were conducted to investigate the stripping properties. High intensity beams of 238U4+ were successfully stripped using hydrogen as stripping gas. The stripping efficiency was significantly increased while the beam quality remained suitable. The new stripper setup and major results achieved during the development are presented. Problems with the fast valves arose while they were used for a longer duration. Another revision of the setup took place to exchange the valves. In parallel, the installation of the required infrastructure for regular operation of the gas stripper using hydrogen was planned.  
slides icon Slides FR1A05 [10.013 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A05  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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FR2A02 Commissioning of the European XFEL FEL, MMI, photon, linac 994
 
  • D. Nölle
    DESY, Hamburg, Germany
  
  The construction of the European XFEL has been finished at the end of 2016 and commissioning has been started. Meanwhile the entire facility, driving 3 free-electron-lasers in the hard and soft X-ray regime, is in operation. This contribution will report on commissioning and transition to operation, as well as on the first user runs.  
slides icon Slides FR2A02 [11.022 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR2A02  
About • paper received ※ 04 September 2018       paper accepted ※ 17 October 2018       issue date ※ 18 January 2019  
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