THPLR —  Poster Session   (29-Sep-16   16:00—17:00)
Chair: L. Popielarski, FRIB, East Lansing, USA
Paper Title Page
THPLR001
 Measurements of the Beam Break-Up Threshold Current at the Recirculating Electron Accelerator S-DALINAC  
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  • T. Kürzeder, M. Arnold, L.E. Jürgensen, J. Pforr, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • F. Hugpresenter
    IKP, Mainz, Germany
  
  Funding: *Supported by the German Federal Ministry for Education and Research (BMBF) under Grant No. 05K13RDA.
Linear accelerators, in particular those with a recirculating design and superconducting cavities, have to deal with the problem of Beam Break-Up (BBU). This instability can limit the maximum beam current in such accelerators. Knowing the effectiveness of prevention strategies is of great interest especially for future accelerators like energy recovery linacs (ERL) which aim for high beam currents. One option is to optimize the cavities and higher order mode couplers of those machines. In addition one may adapt the beam line lattice for further suppressing BBU. The superconducting recirculating accelerator S-DALINAC at the Technische Universität Darmstadt provides electron beams in c.w. for nuclear physics experiments since 1991. As the SRF components were never optimized for higher order mode suppression the S-DALINAC suffers from BBU at relatively low beam currents of a few μA. While those currents are sufficient for most nuclear physics experiments we can investigate BBU with respect to the beam optics. We will report on first measurements of threshold currents at different beam energies of the S-DALINAC. The results of a first test to increase the BBU limit by using skew quadrupoles will be presented. 		 
slides icon Slides THPLR001 [1.473 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP04  
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THPLR002
 Status and Operation of the ALBA Linac  
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  • R. Muñoz Horta, D. Lanaia, F. Pérez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  The pre-injector of the ALBA Light Source is a Linac that delivers electrons up to a maximum energy of 125 MeV. It consist in a pre-bunching, a bunching and two accelerating sections feed by two 35 MW klystrons. Since July 2014, ALBA is operating in top-up mode, and the Linac is delivering 110 MeV electrons in multibunch mode every 20 minutes. Recently, new injection modes have been implemented and successfully tested. For one side, injection to the ALBA Booster is now also available with only one of the two klystrons in operation, and the Linac delivering a 67 MeV beam. On the other hand, the Linac single bunch mode has been integrated to the top-up operation application. By means of an algorithm, single bunch mode operation provides any kind of filling pattern in the ALBA storage ring, with single bunch shots injected to those buckets with lowest current. The performance of the Linac beam operated in these different modes is reported.  
slides icon Slides THPLR002 [0.604 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP05  
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THPLR003 Fabrication and High-Gradient Testing of an Accelerating Structure Made From Milled Halves 845
 
  • W. Wuensch, T. Argyropoulos, N. Catalán Lasheras, D. Esperante Pereira, J. Giner Navarro, A. Grudiev, G. McMonagle, I. Syratchev, B.J. Woolley, H. Zha
    CERN, Geneva, Switzerland
  • T. Argyropoulos, D. Esperante Pereira, J. Giner Navarro
    IFIC, Valencia, Spain
  • G.B. Bowden, V.A. Dolgashev, A.A. Haase
    SLAC, Menlo Park, California, USA
  • P.J. Giansiracusa, T.G. Lucas, M. Volpi
    The University of Melbourne, Melbourne, Victoria, Australia
  • R. Rajamaki
    Aalto University, School of Science and Technology, Aalto, Finland
  • X.F.D. Stragier
    TUE, Eindhoven, The Netherlands
  
  Accelerating structures made from parts which follow symmetry planes offer many potential advantages over traditional disk-based structures: more options for joining (from bonding to welding), following this more options for material state (heat treated or not) and potentially lower cost since structures can be made from fewer parts. An X-band structure made from milled halves, and with a standard benchmarked CLIC test structure design has been fabricated and high-gradient tested in the range of 100 MV/m.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR003  
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THPLR004 Development of 1.3 Ghz Single-Cell Superconducting Cavities With Nb Material Developed by Ulba Metallurgical Plant 849
 
  • T. Ota, N. Kuroiwa, S. Nomura, Y. Otani, M. Takasaki, M. Yamada
    Toshiba, Yokohama, Japan
  • H. Hayano, T. Saekipresenter
    KEK, Ibaraki, Japan
  • Y.V. Krygin, V. Kuznetsov, A.A. Tsorayev
    Ulba Metallurgical Plant, Ust-Kamenogorak, Kazakhstan
  • Y. Shirota
    BE International Corporation, Tokyo, Japan
  • T. Tosaka
    Toshiba Corporation, Power And Industrial Systems Research and Development Center, Yokohama, Japan
  
  TOSHIBA has been developing high purity niobium (Nb) material for superconducting cavities with ULBA Metallurgical Plant (UMP) since 2008. Recently, we have produced the high purity Nb plates. Two 1.3 GHz single-cell superconducting cavities using UMP's Nb plates have been fabricated by TOSHIBA and RF tested at High Energy Accelerator Research Organization (KEK). One of the cavities has achieved the accelerating gradient of Eacc=31.8 MV/m. The development of high purity Nb plates, details of the fabrication of the cavities and the RF test results are presented in this article.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR004  
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THPLR006 Design Study of a Test Cavity for Evaluating RF Critical Magnetic Field of Thin-Film Superconductor 852
 
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
  • H. Hayano, S. Kato, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • T. Higashiguchi
    Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
  • M. Hino
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  
  Superconducting cavities of higher gradient has been demanded in various fields of the accelerator science. Also, according to the Technical Design Report (TDR) of International Linear Collider (ILC), the higher gradient of 45 MV/m is required in the second stage of ILC. To realize such higher gradient, several methods are proposed. One of such methods is to coat multi-layer thin-film superconductor on the inner surface of RF cavity where the thin film increases the RF critical field on the inner surface of the cavity. To demonstrate the RF performance of thin-film structure on a small coupon sample, we designed the RF mushroom-shaped cavity with which the RF critical magnetic field is measured on a thin-film coupon sample set on the inner surface of the cavity. If the RF cavity is cooled down below the critical temperature of thin-film superconductor with supplying RF power, the heat dissipation might be measured on the coupon sample in the cavity. We designed the shape of the cavity so as to produce a strong RF magnetic field parallel to the sample surface efficiently. We report the design, manufacturing and RF property measurements of the cavity in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR006  
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THPLR007 Dark Current Studies in ILC Main Linac 855
 
  • A.I. Sukhanov, I.L. Rakhno, N. Solyak, I.S. Tropin
    Fermilab, Batavia, Illinois, USA
  
  Studies and optimization of design of the International Linear Collider (ILC) based on the TESLA-type 9-cell 1.3 GHz superconducting RF (SRF) cavities are currently underway. Dark current electron generated by field emission (FE) in SRF cavities can be captured and accelerated in the main ILC linac up to very high energy before they are removed by focusing and steering magnets. Dark current electrons, interacting with the materials surrounding SRF cavities, produce electromagnetic showers and contribute to the radiation in the main ILC tunnel. In this paper present preliminary results of the simulation study of dark current in the ILC linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR007  
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THPLR008 3-Cell Superconducting Traveling Wave Cavity Tuning at Room Temperature 858
 
  • R.A. Kostin
    LETI, Saint-Petersburg, Russia
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • T.N. Khabiboulline, A.M. Rowe, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by US DOE SBIR # DE-SC0006300
A superconducting traveling wave (SCTW) cavity with a feedback waveguide will support a higher average acceleration gradient compared to conventional SRF standing wave cavities [1]. Euclid Techlabs, in collaboration with Fermilab, previously demonstrated a high accelerating gradient in a single cell cavity with a feedback waveguide [2], and the new waveguide design did not limit the cavity performance. The next step is high gradient traveling wave SRF cavity test. A 3-Cell SCTW cavity was designed and developed [3] to demonstrate the SRF traveling wave regime. Two Nb SCTW cavities were built, characterized and cold tested in 2016. This paper presents the results of cavity inspection, field flatness analysis, along with a discussion of the tuning procedure. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR008  
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THPLR009 A Compact Muon Accelerator for Tomography and Active Interrogation 861
 
  • R.W. Garnett, S.S. Kurennoy, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
  • K. Hasegawa
    JAEA, Ibaraki-ken, Japan
  • S. Portillo, E. Schamiloglu
    University of New Mexico, Albuquerque, USA
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Funding: This work is supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
Muons have been demonstrated to be great probes for imaging large and dense objects due to their excellent penetrating ability. At present there are no muon accelerators. Development of a compact system that can produce an intense beam of accelerated muons would provide unique imaging options for stockpile stewardship while delivering minimal radiation dose, as well as various homeland-security and industrial applications. Our novel compact accelerator approach allows a single linac to be used to first accelerate an electron beam to 800 MeV to generate muons by interacting with a production target in a high-field solenoid magnet and then to collect and accelerate these low-energy muons to 1 GeV to be used for imaging or active interrogation. The key enabling technology is a high-gradient accelerator with large energy and angular acceptances. Our proposed solution for efficient acceleration of low-energy muons is a 0-mode linac coupled with conventional electron RF accelerating structures to provide a compact system that could deliver a controllable high-flux beam of muons with well-defined energy to allow precise radiographic inspections of complicated objects. The details of the conceptual design will be discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR009  
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THPLR010
 Design and Commissioning of FRIB Multipacting-Free Fundamental Power Coupler  
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  • Z. Zheng, J.T. Popielarski, K. Saito, S. Stark, T. Xu, Y. Yamazaki
    FRIB, East Lansing, USA
  
  Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The original Fundamental Power Coupler (FPC) of Half-Wave Resonator (HWR) for the Facility of Rare Isotope Beams (FRIB) requires multipacting conditioning at operating RF power which is up to 5 kW Continue Wave (CW). Conditioning takes a lot of time and RF power, and its elimination is highly desirable. To significantly shorten the RF conditioning, we developed a multipacting-free coupler design. This paper reports the latest progress in the optimization and prototype tests of multipacting-free coupler. The choke structure is removed and coupler geometry is further modified to protect the coupler RF window from the electron bombardment. The comparison result of multipacting-free coupler with original coupler was performed on automatic conditioning system, which showed significantly time reducing for RF conditioning. 		 
slides icon Slides THPLR010 [2.442 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP10  
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THPLR011 Traveling Wave Accelerating Structure Power Input Calculation With Equivalent Circuit Method 864
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  • S.V. Matsievskiy, V.I. Kaminskiy
    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. This paper describes an attempt to create more universal and user-friendly software application for calculating electrical field distribution in accelerating structures, provides mathematical equations this software is based on. The resulting application may be used for preliminary calculations of acceleration structures and help to determine cells electrodynamic parameters reducing overall design time.  
poster icon Poster THPLR011 [0.789 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR011  
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THPLR012 Beam-Loading Compensation of a Multi-Bunch Electron Beam by Using RF Amplitude Modulation in Laser Undulator Compact X-Ray Source (LUCX) 867
 
  • M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • M. Washio
    Waseda University, Tokyo, Japan
  
  Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source via laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. In here, a multi-bunch electron beam is generated by a 3.6cell photo-cathode RF-gun and accelerated to 18-24MeV by a 12cell booster. And then 6-10 keV X-rays are generated by LCS between the beam and a laser pulse stored in a 4-mirror planar optical cavity. Our aim is to take a phase contrast image with Talbot interferometer within a few minutes at present. The target flux of X-ray is 1.7x107 photons/pulse with 10% bandwidth. For an electron beam, the target of the intensity is 500nC/pulse with 1000 bunches at 30 MeV. Presently, we have achieved the generation of 24MeV beam with total charge of 600nC in 1000bunches. The energy difference is within 1.3% peak to peak. The beam-loading is compensated by delta T method and amplitude modulation(AM) of the RF pulse*. However there is the energy difference at the RF-gun. It is assumed that this causes the reduction of the X-ray flux due to change of the focused beam size. To reduce the energy difference, AM is also applied to the RF pulse for the gun. We will show the results of the beam-loading compensation and the generation of X-rays.
* Y. Yokoyama et al. , Proceedings IPAC2011, TUPC059 (2011). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR012  
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THPLR013 LEETCHI: The High Current Electron Source for the CLIC Drive Beam Injector 870
 
  • K. Pepitone, S. Döbert
    CERN, Geneva, Switzerland
  • B. Cadilhon, B. Cassany, J. Gardelle
    CEA, LE BARP cedex, France
  
  LEETCHI is a source which will produce 140 keV, 5 A, 140 μs electron beams at a repetition rate of 50 Hz. The shot to shot and flat top current stability of this drive beam injector for CLIC has to be better than 0.1% and a geometrical emittance of 14 mm mrad is expected. The development of a high voltage modulator, to achieve those requirements, is ongoing. A small test stand has been built which allows to diagnose and dump the beam produced by the thermionic cathode. The thermionic cathode is equipped with a grid which will allow us to control the current and eventually to have a feedback on the flattop shape. The beam dump, made of graphite, has been designed using two different codes, the Monte Carlo code GEANT4 to simulate the energy deposition and ANSYS used to simulate the thermal resistance of the graphite due to the long pulse duration. The geometry has been optimized with the ray tracing code EGUN and the 2D PIC-code MAGIC. All these simulations allowed us to optimize the geometry of the gun and to develop diagnostics which must survive to the heat deposition. Finally, the first electrical measurements of the beam will be presented.  
poster icon Poster THPLR013 [19.847 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR013  
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THPLR014 Laser-Driven Dielectric Nano-Beam Accelerator for Radiation Biology Researches 873
 
  • K. Koyama, M. Yoshida
    KEK, Ibaraki, Japan
  • Z. Chen, H. Okamoto
    The University of Tokyo, Tokyo, Japan
  • M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  
  Funding: This work was partly supported by JSPS KAKENHI (B)(Grant-in-Aid for Scientific Research) Grant Number 15H03595.
Since a laser-driven dielectric accelerator (LDA) is most likely to deliver a nano-beam with a small scale device, a combination of the LDA and a biological cell observation device such as a fluorescence microscope seems to be a powerful tool for radiation biology researches. The LDA consists of single or a pair of binary-blazed transmission grating. In case of normal incidence, a grating constant must be the same with a laser wavelength to synchronize with the electron and an acceleration field. Although demonstration experiments have been published from SLAC and MPQ, there are many problems to be solved, especially in the non-relativistic energy region. A crucial problem is to make it clear whether electrons are accelerated with negligibly small wiggling or lateral shift. We are simulating at various conditions with the aid of CST-code. We also analyze an oblique incidence (OI) scheme for the efficient acceleration of slow electron. The OI-scheme enables to use the grating of larger grating constant. Adoption of the large grating constant makes it easy to fabricate the grating. Besides analytical works, we are making gratings and developing an Yb-doped fiber laser for the acceleration experiment. Gratings of two different materials, a glass silica and crystal silica, were fabricated by the e-beam lithography technique. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR014  
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THPLR015 Fifth-Order Moment Correction for Beam Position and Second-Order Moment Measurement 876
 
  • K. Yanagida, H. Hanaki, S. Suzuki
    JASRI/SPring-8, Hyogo-ken, Japan
  
  For precise beam position measurement using a beam position monitor (BPM), a recursive correction which is expressed by the higher-order polynomials of beam positions are usually adopted. We recognized that the higher-order polynomials came from the higher-order moments and that beam position measurement is consequently influenced by a transverse beam shape. To investigate what order was required for adequate correction, we performed a successive iteration for the six-electrode BPM holding an inner radius of 16mm (circular cross-section). The successive iteration is a method to obtain a self-consistent solution for the higher-order correction. An amplitude of static electric field due to a beam charge was calculated by two-dimensional mirror charge method. As a result of the successive iteration, the convergence region was large enough for ordinary measurements (from lower than -5mm to higher than 5mm horizontally and vertically). In the convergence region the root mean square of the differences between the set and calculated vertical position were obtained as 0.487mm (without correction), 0.030mm (with third-order correction) and 0.003mm (with fifth-order correction).  
poster icon Poster THPLR015 [6.049 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR015  
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THPLR018 HOM Suppression Improvement for Mass Production of EXFEL Cavities at RI 879
 
  • A.A. Sulimov, J.H. Thie
    DESY, Hamburg, Germany
  • M. Pekeler, D. Trompetter
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  
  During cold RF tests of the European XFEL (EXFEL) cavities at DESY it was observed that the damping of the second monopole mode (TM011) showed the largest variation, which was sometimes up to 2-3 times lower than the originally allowed limit. It was concluded that this TM011-damping degradation was caused by cavity geometry deviation within the specified mechanical tolerances. The particular influence of different mechanical parameters was analyzed and additional RF measurements were carried out to find the most critical geometry parameters. Stability of the equator welding and regularity of chemical treatment were investigated for different cavity cells. In spite of the high fabrication rate during EXFEL cavity mass production the TM011 suppression was improved to an acceptable level.  
poster icon Poster THPLR018 [0.378 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR018  
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THPLR019 A Laser Pulse Controller for the Injector Laser at FLASH and European XFEL 882
 
  • C. Grün, S. Schreiber, T. Schulz
    DESY, Hamburg, Germany
  
  FLASH is a multi-beamline free-electron laser user facility which provides femtosecond long high brilliant photon pulses in the extreme-UV and soft-X ray wavelength range. One pulsed superconducting linac accelerates electron bunches for two undulator beamlines, while a third beamline is under construction. Within each RF-pulse, trains of hundreds of electron bunches are produced in a photo-cathode RF gun, accelerated in the linac and distributed by fast kickers into the undulator beamlines. In order to fulfill the parameter ranges of the multiple user experiments each bunch train can be tuned individually in bunch number from 0 - 800, spacing from 1 μs - 25 μs and intensity from 0.1 nC - 1 nC. To make this possible, three injector laser systems are used and this allows FLASH to vary independently the laser settings for the designated undulator beamlines. A laser controller has been developed to make a multi-users operation mode possible. The controller uses a Field Programmable Gate Array (FPGA) to control the time structure of the laser pulses and it provides the interface for the timing and the machine protection system. The controller has been implemented using the MicroTCA.4 technology. The controller was ported to the injector laser system at the European XFEL facility and is in operation since end 2015.  
poster icon Poster THPLR019 [1.967 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR019  
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THPLR020 Status and Progress of FRIB High Level Controls 885
 
  • G. Shen, E.T. Berryman, D. Chabot, M.A. Davidsaver, K. Fukushima, Z.Q. He, M. Ikegami, M.G. Konrad, D. Liu, D.G. Maxwell, V. Vuppala
    FRIB, East Lansing, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
FRIB, which is a new heavy ion accelerator facility to provide intense beams of rare isotopes, is currently under construction at Michigan State University. Its driver linac accelerates all stable ions up to uranium, and targets to provides a CW beam with the energy of 200 MeV/u and the beam power of 400 kW. The beam commissioning of the its Front-End has been planned to start from Middle of 2016. The high level controls for incoming commissioning is under active development and deployment. The latest status progress will be presented in this paper. 		 
poster icon Poster THPLR020 [2.291 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR020  
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THPLR021 Identification of Emitting Sources of Dark Currents From Gridded Thermionic Electron Gun and Measures to Suppress Dark Currents From Electron Gun in SPring-8 Linear Accelerator 888
 
  • T. Magome, H. Hanaki, T. Kobayashi, S. Suzuki, T. Taniuchi
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The dark current is emitted from a gridded thermionic electron gun although the grid-electrode potential against the cathode is negative enough to suppress the cathode emission current. This dark current in the SPring-8 linear accelerator caused satellite bunches unignorable for precise experiments in the downstream electron storage ring. The dark current has been investigated by means of our electron-gun test equipment applying a DC accelerator voltage to the electron gun. The investigations revealed that the dark current was generated from the wehnelt electrode, the gird electrode, and the cathode surface. The dark current from the wehnelt electrode was decreased under the measurement limit 2·10-15 A by replacing the wehnelt and the anode electrodes with new electro-polished ones. The dark current from the cathode surface was reduced by lowering the grid-electrode potential against the cathode down to -160 V. To reduce the dark current from the grid electrode, the surface of the grid electrode was significantly smoothed by electro-polishing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR021  
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THPLR023 The ARIEL Radioactive Ion Beam Transport System 891
 
  • M. Marchetto, T.J. Alderson, F. Ames, R.A. Baartman, J.D. Chak, P.E. Dirksen, T.G. Emmens, G.W. Hodgson, T. Hruskovec, M. Ilagan, R.E. Laxdal, N. Muller, D. Preddy, D. Rowbotham, S. Saminathan, Q. Temmel, V.A. Verzilov, D. Yosifov
    TRIUMF, Vancouver, Canada
  
  The Advanced Rare IsotopE Laboratory (ARIEL) is going to triple the radioactive ion beam (RIB) production at TRIUMF. The facility will enable multi-user capability in the Isotope Separation and ACceleration (ISAC) facility by delivering three RIBs simultaneously. Two new independent target stations will generate RIBs using a proton driver beam up to 50 kW from the 500 MeV cyclotron and an electron driver beam for photo-fission from the new superconducting e-linac in addition to the existing ISAC RIB production. The multi-user capability is enabled by a complex radioactive ion beam transport switchyard consisting entirely of electrostatic optics. This system includes two separation stages at medium and high resolution with the latter achieved by a mass separator designed for an operational resolving power of 20000 for a 3 micrometer transmitted emittance. Part of the system also includes an Electron Beam Ion Source (EBIS) charge breeder fed by a radio frequency cooler that allows the post-acceleration of heavy masses. Beam selection downstream of the EBIS is achieved by means of a Nier type separator. The facility is in a detailed design stage and some tests, procurements and partial installation are foreseen by the end of 2016.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR023  
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THPLR024 SPIRAL2 Project: Integration of the Accelerator Processes, Construction of the Buildings and Process Connections 894
 
  • P. Anger, P. Bisson, O. Danna, X. Hulin, J.-M. Lagniel, S. Montaigne, F. Perocheau, E. Petit, L. Roupsard
    GANIL, Caen, France
  
  The GANIL SPIRAL 2 Project is based on the construction of a superconducting ion CW LINAC (up to 5 mA - 40 MeV deuteron and 33 MeV proton beams, up to 1 mA - 14.5 MeV/u heavy ion beams) with two experimental areas named S3 ('Super Separator Spectrometer' for very heavy and super heavy element production) and NFS ('Neutron For Science'), The building studies as well as the accelerator and experimental equipment integration started in 2009. The ground breaking started at the end of 2010. The integration task of the different equipments into the buildings is managed by a trade-oriented integration unit gathering the accelerator integration team, the building prime contractor and a dedicated contracting assistant. All work packages are synthesized at the same time using 3D models. 3D tools are used to carry out integration, synthesis, process connections and the preparation of the future assembly. Since 2014, the buildings and process connections are received and the accelerator installation is well advanced. This contribution will describe these 3D tools, the building construction, the process connection status and our experience feedback.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR024  
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THPLR025 Modernisation of the 108 MHz RF Systems at the GSI UNILAC 898
 
  • B. Schlitt, G. Eichler, S. Hermann, M. Hoerr, M. Mueh, S. Petit, A. Schnase, G. Schreiber, W. Vinzenz, J. Zappai
    GSI, Darmstadt, Germany
  
  A substantial modernisation of the RF systems at the 108 MHz Alvarez type post-stripper section of the GSI heavy ion linac UNILAC was launched in 2014 to prepare the existing facility for the future FAIR operation. A new 1.8 MW RF cavity amplifier prototype for low duty-cycle operation (2 ms pulse length at 10 Hz repetition rate) based on the widely-used tetrode TH558SC was designed and built by THALES and is under commissioning. A call for tenders was started for a 150 kW solid state driver amplifier. An RF test bench for the amplifier prototypes is in preparation at GSI including new control racks, commercial grid power supplies, and a modern PLC system for amplifier control. The existing powerful 1 MVA anode power supplies will be reused and are also being equipped with new PLC systems. The development of a digital low-level RF system based on the MTCA.4 standard and commercial vector modulator and FPGA boards was started. Status and details of the modernisation as well as first commissioning results of the new high power amplifier prototype will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR025  
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THPLR026 Radio Frequency Surface Plasma Source With Solenoidal Magnetic Field 902
 
  • V.G. Dudnikov, R.P. Johnson
    Muons, Inc, Illinois, USA
  • G. Dudnikova
    UMD, College Park, Maryland, USA
  • G. Dudnikova
    ICT SB RAS, Novosibirsk, Russia
  • B. Han, S. Murrey, C. Stinson
    ORNL RAD, Oak Ridge, Tennessee, USA
  • T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: The work was supported in part by US DOE Contract DE-AC05-00OR22725 and by STTR grant, DE-SC0011323.
Operation of Radio Frequency surfaces plasma sources (RF SPS) with a solenoidal magnetic field are described. RF SPS with solenoidal and saddle antennas are discussed. Dependencies of beam current and extraction current on RF power, gas flow, solenoidal magnetic field are presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR026  
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THPLR027 Progress Towards a 2.0 K Half-Wave Resonator Cryomodule for Fermilab's PIP-II Project 906
 
  • Z.A. Conway, A. Barcikowski, G.L. Cherry, R.L. Fischer, B.M. Guilfoyle, C.S. Hopper, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, P.N. Ostroumov, T. Reid
    ANL, Argonne, Illinois, USA
  • V.A. Lebedev, A. Lunin
    Fermilab, Batavia, Illinois, USA
  
  Funding: This material is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and Office of High-Energy Physics, Contracts No. DE-AC02-76-CH03000 and DE-AC02-06CH11357.
In support of Fermilab's Proton Improvement Plan-II project Argonne National Laboratory is constructing a superconducting half-wave resonator cryomodule. This cryomodule is designed to operate at 2.0 K, a first for low-velocity ion accelerators, and will accelerate ≥1 mA proton/H− beams from 2.1 to 10.3 MeV. Since 2014 the construction of 9 162.5 MHz b = 0.112 superconducting half-wave resonators, the vacuum vessel and the majority of the cryomodule subsystems have been finished. Here we will update on the status of this work and report on preliminary cavity test results. This will include cavity performance measurements where we found residual resistances of < 3 nanoOhms at low fields and peak voltage gains of 5.9 MV, which corresponds to peak surface fields of 134 MV/m and 144 mT electric and magnetic respectively. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR027  
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THPLR028 Simulation of Mechanical Oscillations in PIP-II Cryomodule Using ACE3P 910
 
  • L. Xiao, O. Kononenko, C.-K. Ng
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the US DOE under contract DE-AC02-76SF00515.
The linac in the PIP-II project at Fermilab consists of different sections of superconducting rf (SRF) cavities that can accelerate the proton beams to 800 MeV. At the end of the linac is a section containing a number of HB (β = 0.92) cryomodules operating at 650 MHz, with each cryomodule consisting of six SRF cavities. Previous calculations have been carried out to determine the mechanical modes of a single cavity in the 650 MHz cryomodule. In this paper, the parallel code suite ACE3P is used to evaluate the mechanical modes for a string of SRF cavities in the 650 MHz cryomodule. The effects of multi cavities on the mechanical mode frequencies and any possible coupling between cavities will be investigated. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR028  
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THPLR029 Update on the SC 325 MHz CH-Cavity and Power Coupler Processing 913
 
  • M. Busch, M. Amberg, M. Basten, F.D. Dziuba, P.A. Mundine, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Funding: Work supported by GSI, BMBF Contr. No. 05P15RFRBA
The 325 MHz CH-Cavity which has been developed and successfully vertically tested at the Institute for Applied Physics, Frankfurt, has reached the final production stage. The helium vessel has been welded to the frontal joints of the cavity and further tests in a horizontal environment are in preparation. Furthermore the corresponding power couplers have been conditioned and tested at a dedicated test stand up to the power level of 40 kW (pulsed) for the targeted beam operation. The final step of the whole prototype development is a beam test with a 11.4 AMeV, 10 mA ion beam at GSI, Darmstadt. 		 
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THPLR030 Performances of the Two First Single Spoke Prototypes for the MYRRHA Project 916
 
  • D. Longuevergne, J.-L. Biarrotte, S. Blivet, P. Duchesne, G. Olry, H. Saugnac
    IPN, Orsay, France
  • Y. Gómez Martínez
    LPSC, Grenoble Cedex, France
  
  Funding: This work is being supported by the Euratom research and training program 2014-2018 under grant agreement N°662186 (MYRTE project)
The MYRRHA project aims at the construction of an accelerator driven system (ADS) at MOL (Belgium) for irradiation and transmutation experiment purposes. The facility will feature a superconducting LINAC able to produce a proton flux of 2.4 MW (600 MeV - 4 mA). The first section of the superconducting LINAC will be composed of 352 MHz (β = 0.37) Single Spoke Resonators (SSR) housed in short cryomodules operating at 2K. After a brief presentation of the cryomodule design, this paper will aim at presenting the RF performances of the SSR tested in vertical cryostat in the framework of European MYRTE project (MYRRHA Research and Transmutation Endeavour) and at comparing experimental results (Lorentz forces, pressure sensitivity, multipacting barriers…) to simulated values. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR030  
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THPLR032 Update on SSR2 Cavity EM Design for PIP-II 920
 
  • P. Berrutti, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Proton Improvement Plan II (PIP-II) is the future plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H− ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. SC linac using five cavity types. One 162.5 MHz half wave resonator, two 325 MHz spoke resonators and two 650 MHz elliptical 5-cell cavities, provide acceleration to 800 MeV. The EM design of the second family of spoke resonator is presented in this paper. The work reported is a thorough electromagnetic study including: the RF parameters, multipacting mitigation and transverse field asymmetry. The cavity is now ready for structural design analysis.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR032  
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THPLR033 R&D Status of the New Superconducting CW Heavy Ion LINAC@GSI 923
SPWR024   use link to see paper's listing under its alternate paper code  
 
  • M. Basten, M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • W.A. Barth, V. Gettmann, S. Mickat, M. Miski-Oglu
    HIM, Mainz, Germany
  • M. Heilmann, S. Mickat, S. Yaramyshev
    GSI, Darmstadt, Germany
  
  For future research in the field of Super Heavy Elements (SHE) a superconducting (sc) continuous wave (cw) ion LINAC with high intensity is highly desirable. Presently a multi-stage R&D program conducted by GSI, HIM and IAP[*] is in progress. The fundamental linac design composes a high performance ion source, a new low energy beam transport line, the High Charge State Injector (HLI) upgraded for cw, and a matching line (1.4 MeV/u) followed by the new sc-DTL LINAC for acceleration up to 7.3 MeV/u. The successful commissioning of the first Crossbar-H-mode (CH) cavity (Demonstrator), in a vertical cryo module, was a major milestone in 2015[**]. The next stage of the new sc cw heavy ion LINAC is the advanced demonstrator comprising a string of cavities and focusing elements build from several short constant-beta sc CH-cavities operated at 217MHz. Currently the first two sc 8 gap CH-cavities are under construction at Research Instruments (RI), Bergisch Gladbach, Germany. The new design without girders and with stiffening brackets at the front and end cap potentially reduces the overall technical risks during the construction phase and the pressure sensitivity of the cavity. The recent status of the construction phase as well as an outlook for further cavity development of the new cw heavy ion LINAC will be presented.
*W.Barth et al.,Further R&D for a new Superconducting cw Heavy Ion LINAC@GSI, IPAC14, THPME004
**F.Dziuba et al.,First Performance Test on the Superconducting 217 MHz CH Cavity at 4K,LINAC16, THPLR033 		 
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THPLR035 FZJ SRF TSR with Integrated LHe Vessel 926
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  
  Single- or Multi-Spoke SRF cavities are one of the basic accelerating structures for the low and intermediate energy part of many accelerators. Different types of external loads on the resonator walls predetermine the main working conditions of the SC cavities. The most important of them are very high electromagnetic fields that result in strong Lorentz forces acting on cavity walls and the pressure on cavity walls from the helium tank that also deforms the cavity shape. For the accelerators operating in pulsed regime the Lorentz forces are the dominant factor. The liquid helium vessel pressure instability even for 2K operations is the source of large microphonics and dominates for cw operation. Here we propose an innovative integrated helium vessel-cavity and stiffener design that will provide an effective passive damping minimizing df/dp ratio. Minimizing df/dp may be accomplished without an enhancement of the structure rigidity, which in turn minimizes the load on the cavity tuner. A separate stiffening scheme reducing Lorentz force cavity detuning to be added without violation of df/dp optimization. The developed at the Research Center in Jülich, Germany (FZJ) the 352 MHz, β=v/c=0.48 Triple-Spoke Resonator was used as an example to demonstrate the proposed conceptual integrated helium vessel-cavity design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR035  
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THPLR036 SRF Low-Beta Elliptical Resonator Two-Ring Stiffening 929
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  • I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Elliptical SRF cavities are the basic accelerating structures for the high energy part of many accelerators. Since a series of external loads on the resonator walls predetermine the main working conditions of the SC cavities the detailed investigation of their mechanical properties should be conducted in parallel with the main RF design. The effects of very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape, the tuning scheme resulting in the change of accelerating field profile and mechanical eigen resonances of cavities which are the main source of the microphonics must be taken into account during integrated design of the resonator and its liquid helium vessel. SRF elliptical cavities for the medium energies (β=v/c is around 0.6) inherently have more flexible shape and their ultimate stiffening with a "standard" stiffening rings installed between resonator cells becomes problematic. The second row of the rings should enhance the overall cavity rigidity. In the paper we report the basic investigations of the cavity two-row ring stiffening using FNAL 650 MHz β=0.61 as an example. The single-cell investigation results were used as the reference to develop the ultimate scheme of the helium vessel structure to ensure the best resonator stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR036  
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THPLR037 Development of a Superconducting Twin Axis Cavity 932
SPWR031   use link to see paper's listing under its alternate paper code  
 
  • H. Park, A. Hutton, F. Marhauser
    JLab, Newport News, Virginia, USA
  • S.U. De Silva, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  
  Superconducting cavities with two separate accelerating axes have been proposed in the past for energy recovery linac applications. While the study showed the advantages of such cavity, the designs present serious fabrication challenges. Hence the proposed cavities have never been built. The new design, elliptical twin cavity, proposed by Jefferson Lab and optimized by Center for Accelerator Science at Old Dominion University, allows similar level of engineering and fabrication techniques of a typical elliptical cavity. This paper describes preliminary LOM and HOM spectrum, engineering and fabrication processes of the twin axis cavity.  
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THPLR038 Resonance Control for Narrow Bandwidth PIP-II Cavities 936
 
  • W. Schappert, J.P. Holzbauer, Y.M. Pischalnikov
    Fermilab, Batavia, Illinois, USA
  
  The PIP-II project at FNAL calls for a SRF pulsed proton driver linac to support the expanding neutrino physics program including DUNE/LBNF. The relatively low beam current and high quality factors called for in the design means that these cavities will be operated with small RF bandwidths, meaning that they will be sensitive to microphonics. Combined with a 20 Hz pulsed operational structure and the use of four different, complex cavity geometries means that resonance control will be extremely challenging. Work is ongoing at FNAL to develop active resonance stabilization techniques using fast piezoelectric tuners in support of PIP-II. These techniques as well as testing and development results using a prototype, dressed low-beta single-spoke cavity will be presented along with an outlook for future efforts.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR038  
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THPLR040 First Vertical Test of Superconducting QWR Prototype at RIKEN 939
 
  • K. Yamada, O. Kamigaito, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe
    RIKEN Nishina Center, Wako, Japan
  • E. Kako, H. Nakai, K. Umemori
    KEK, Ibaraki, Japan
  • A. Miyamoto, K. Sennyu, T. Yanagisawa
    MHI-MS, Kobe, Japan
  
  Development of a superconducting quarter-wavelength resonator (SC-QWR) was started at RIKEN Nishina Center to realize a low-velocity part of high-intensity ion linac. First prototype of the SC-QWR, frequency of which is 75.5 MHz, is fabricating now*. Preparation of its partial components such as outer conductor, stem, bottom plate, and top plate was almost completed, and we are now studying a low-power RF property by clamping the every components as an assembly to obtain data for frequency tuning. After the adjustment of geometry of components and welding them, surface treatment by buffered chemical polishing and high-pressure rinsing will be performed in the summer. Preparation of vertical test for the SC-QWR is also in progress at KEK. The first result of vertical test for the prototype of SC-QWR will be presented in this contribution. This work was funded by the ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).
* N. Sakamoto et al., Proceedings of SRF2015, WEBA06. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR040  
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THPLR041 650 MHz Elliptical Superconducting RF Cavities for PIP-II Project 943
 
  • I.V. Gonin, E. Borissov, A. Grassellino, C.J. Grimm, V. Jain, S. Kazakov, V.A. Lebedev, A. Lunin, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, G.V. Romanov, A.M. Rowe, N.K. Sharma, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  The PIP-II 800 MeV linac employs 650 MHz elliptical 5-cell CW-capable cavities to accelerate up to 2 mA peak beam current of H− in the energy range 185 - 800 MeV. The low beta (LB) βG = 0.61 portion should accelerate from 185 MeV-500 MeV using 33 LB dressed cavities in 11 cryomodules. The high beta (HB) βG = 0.92 portion of the linac should accelerate from 500 to 800 MeV using 24 HB dressed cavities in 4 cryomodules. The development of both LB and HB cavities is going on under IIFC collaboration. The development of LB cavity initiated at VECC Kolkatta and HB cavity is going at RRCAT, Indore. This paper present design methodology adopted starting from RF design to get mechanical dimensions of the RF cells and then explains dressing of the cavity for both low beta and high beta cavities. Further the tuner design and its integration to the dressed cavity is discussed. Paper also explains the salient design features of these dressed cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR041  
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THPLR042 Beam Dynamics Studies for a Compact Carbon Ion Linac for Therapy 946
 
  • A.S. Plastun, B. Mustapha, A. Nassiri, P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  • L. Faillace, S.V. Kutsaev, E.A. Savin
    RadiaBeam, Santa Monica, California, USA
  • E.A. Savin
    MEPhI, Moscow, Russia
  
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under Accelerator Stewardship Grant, Proposal No. 0000219678
Feasibility of an Advanced Compact Carbon Ion Linac (ACCIL) for hadron therapy is being studied at Argonne National Laboratory in collaboration with RadiaBeam Technologies. The 45-meter long linac is designed to deliver 109 carbon ions per second with variable energy from 45 MeV/u to 450 MeV/u. S-band structure provides the acceleration in this range. The carbon beam energy can be adjusted from pulse to pulse, making 3D tumor scanning straightforward and fast. Front end accelerating structures such as RFQ, DTL and coupled DTL are designed to operate at lower frequencies. The design of the linac was accompanied with extensive end-to-end beam dynamics studies which are presented in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR042  
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THPLR043 EPICS IOC Prototype of FRIB Machine Protection System 949
 
  • L. Wang, M. Ikegami, Z. Li, G. Shen, S. Zhao
    FRIB, East Lansing, USA
  • M.A. Davis
    NSCL, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The FRIB Machine Protection System (MPS) is designed to protect accelerator components from damage by the beam in case of operating failure. MPS includes master and slave nodes, which are controlled by MPS IOC. In this paper, we present design of MPS IOC and status of its prototyping. 		 
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THPLR044 First Performance Test on the Superconducting 217 MHz CH Cavity at 4.2 K 953
SPWR013   use link to see paper's listing under its alternate paper code  
 
  • F.D. Dziuba, M. Amberg, M. Basten, M. Busch, H. Podlech
    IAP, Frankfurt am Main, Germany
  • W.A. Barth, M. Miski-Oglu
    GSI, Darmstadt, Germany
  • W.A. Barth, M. Miski-Oglu
    HIM, Mainz, Germany
  
  Funding: HIM, GSI, BMBF Contr. No. 05P15RFRBA, EU Project MYRTE
At the Institute for Applied Physics (IAP) of Frankfurt University a superconducting (sc) 217 MHz Crossbar-H-mode (CH) cavity with 15 accelerating cells and a gradient of 5.5 MV/m has been designed. The cavity is the key component of the demonstrator project at GSI which is the first stage to a new sc continuous wave (cw) linac for the production of Super Heavy Element (SHE) in the future. A successful and reliable beam operation of this first prototype will be a milestone on the way to the proposed linac. After fabrication at Research Instruments (RI) GmbH, Germany, the cavity without helium vessel has been commissioned at the new cryogenic test facility of the IAP with low level rf power at 4 K. The results of this first cold test will be presented in this contribution. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR044  
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THPLR045 Operation Mode and Machine State Control for FRIB Driver Linac Operation 956
 
  • M. Ikegami, D. Dudley, M.G. Konrad, Z. Li, G. Shen, V. Vuppala
    FRIB, East Lansing, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
FRIB is a heavy ion linac facility to accelerate all stable ions up to 200 MeV/u with the beam power of 400 kW under construction at Michigan State University. It is required for FRIB driver linac to support various modes of operation with different ion species, charge states, beam energy and so on to meet requirements from experiments. In this paper, we describe overall design of operation modes, machine states, and software to manage transitions of those mitigating the risk of machine damage in FRIB. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR045  
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THPLR046 FRIB Fast Machine Protection System: Engineering for Distributed Fault Monitoring System and Light Speed Response 959
 
  • Z. Li, L.R. Dalesio, M. Ikegami, S.M. Lidia, L. Wang, S. Zhao
    FRIB, East Lansing, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB), a high-power, heavy ion facility, can accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Its fast protection system is required to detect failure and remove beam within 35 μs to prevent damage to equipment. The fast protection system collects OK/NOK inputs from hundreds of devices, such as low level RF controllers, beam loss monitors, and beam current monitors, which are distributed over 200 m. The engineering challenge here is to design a distributed control system to collect status from these devices and send out the mitigation signals within 10 μS timing budget and also rearm for the next pulse for 100 Hz beam (10 mS). This paper describes an engineering solution with a master-slave structure adopted in FRIB. Details will be covered from system architecture to FPGA hardware platform design and from communication protocols to physical interface definition. The response time of ~9.6μS from OK/NOK inputs to mitigation outputs is reached when query method is used to poll the status. A new approach is outlined to use bi-direction loop structure for the slave chain and use streaming mode for data collection from slave to master, ~3μS response time are expected from this engineering optimization. 		 
poster icon Poster THPLR046 [1.872 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR046  
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THPLR047 The Beam Energy Feedback System in Beijing Electron Positron Collider II Linear Accelerator 962
SPWR021   use link to see paper's listing under its alternate paper code  
 
  • S.Z. Wang, Y.L. Chi, X. Huang
    IHEP, Beijing, People's Republic of China
  
  The beam energy feedback system in Beijing electron positron collider II (BEPCII) linear accelerator consists of three parts. They are the beam energy measurement In-put/Output Controller (BEM IOC), the Graphical User Interface (GUI) based on Qt platform and the phasing system. This article describes the implementation of this system and the online testing which has been passed on March 16th, 2016. By using this feedback system, the injection rate and the energy fluctuation of the injection beam has been improved a lot. Now this system is steady running in the control room of BEPCII linear accelerator.  
poster icon Poster THPLR047 [0.569 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR047  
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THPLR048 Development of a Digital LLRF Control System at LNL 966
SPWR009   use link to see paper's listing under its alternate paper code  
 
  • S. Pavinato, M. Betti, D. Bortolato, F. Gelain, D. Marcato, D. Pedretti
    INFN/LNL, Legnaro (PD), Italy
  • M.A. Bellato, R. Isocrate
    INFN- Sez. di Padova, Padova, Italy
  • M. Bertocco
    UNIPD, Padova (PD), Italy
  
  The new Low-Level Radio Frequency (LLRF) control system for linear accelerator at Legnaro National Laboratories (LNL) of INFN is presently being commissioned. A digital Radio Frequency (RF) controller was implemented. Its goal is to stabilize the amplitude, the phase and the frequency of the superconducting cavities of the Linac. The resonance frequency of the low beta cavities is 80 MHz, while medium and high beta cavities resonate at 160 MHz. Each RF controller controls at the same time eight different cavities. The hardware complexity of the RF controller (RF IOC) is reduced by adopting direct RF sampling and the RF to baseband conversion method. The main hardware components are RF ADCs for the direct undersampling of the signals picked up from cavities, a Xilinx Kintek 7 FPGA for the signal processing and DACs for driving the power amplifiers and hence the cavities. In the RF IOC the serial communication between FPGA and ADCs and between FPGA and DACs is based on JESD204b standard. An RF front-end board (RFFE) is placed between cavities and the RF IOC. This is used to adapt the power level of the RF signal from the cavities to the ADCs and from the DACs to the power amplifiers. This paper addresses the LLRF control system focusing on the hardware design of the RF IOC and RFFE boards and on the first test results carried out with the new controller.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR048  
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THPLR049 Tuning the IFMIF 5MeV RFQ Accelerator 969
 
  • A. Palmieri, F. Grespanpresenter, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  
  In order to allow proper operation of the IFMIF RFQ, it is necessary to perform a campaign of RF measurements on the cavity aimed, on one hand, at determining the basic RF parameters (frequency, Q0, etc.), on the other hand at verifying the fulfilment of the voltage law within the specified admitted range (±2% target value, ±4% acceptance value) of any of the perturbative components upon successive tuner settings as predicted by the tuner algorithm. These measurements also involve the determination of the proper depth of the end plates and the positioning and length of the Dipole Stabilizers (if any). In this contribution the tuning procedure and the results of such measurements will be presented for the case of the IFMIF RFQ will be described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR049  
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THPLR050 IFMIF RFQ Module Characterization via Mechanical and RF Measurements 972
 
  • L. Ferrari, A. Palmieri, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • R. Dima, A. Pepato, A. Prevedello, E. Udup
    INFN- Sez. di Padova, Padova, Italy
  
  The RFQ of the IFMIF/EVEDA project is a 9.9 m long cavity able to accelerate a 130 mA deuteron beam from the input energy of 100 keV to the output energy of 5 MeV. Such RFQ operates at the frequency of 175 MHz and is composed of 18 mechanical modules approximately 0.55 m long each. The RFQ realization involves the I.N.F.N. Sections of Padova, Torino and Bologna, as well as the Legnaro National Laboratories (L.N.L.). The metrological measurements via CMM (Coordinate Measuring Machine) provided to be a very effective tool both for quality controls along the RFQ production phases and in the reconstruction of the cavity geometric profile for each RFQ module. The scans in the most sensitive regions with respect to RF frequency, such as modulation, tips, base-vane width and vessel height provided the values of the cavity deviations from nominal geometry to be compared with design physic-driven tolerances and with RF measurements. Moreover, the comparison between mechanical and RF measurements suggests a methodology for the geometric reconstruction of the cavity axis and determines the final machining of the end surfaces of each module in view of the coupling with the adjacent ones. In this paper a description of the meteorological procedures and tests and of the RFQ along its production and assembly phases will be described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR050  
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THPLR051 High-Power RF Test of IFMIF-EVEDA RFQ at INFN-LNL 975
 
  • E. Fagotti, L. Antoniazzi, M.G. Giacchini, F. Grespanpresenter, M. Montis, A. Palmieri
    INFN/LNL, Legnaro (PD), Italy
  
  A partial test at full power and CW duty cycle will be performed at INFN-LNL on the last elements of the IFMIF RFQ, approximately two meters of structure, using a specific electromagnetic boundary element on the low energy end. The aim is to reach, in the RFQ coupled with its power coupler system, after an adequate period of conditioning, cw operation at nominal field level (132 kV between electrodes) for at least two hours without breakdown. The description of the experimental setup and procedure, as well as the main results of the conditioning procedure will be reported in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR051  
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THPLR054 Recent RF and Mechanical Developments for the ESS RFQ 978
 
  • N. Misiara, A. Albéri, G. Bourdelle, A.C. Chauveau, D. Chirpaz-Cerbat, M. Desmons, A.C. France, M. Lacroix, P.-A. Leroy, J. Neyret, G. Perreu, O. Piquet, B. Pottin, H. Przybilski, N. Sellami
    CEA/IRFU, Gif-sur-Yvette, France
  
  The ESS Radio-Frequency Quadrupole (RFQ) is a 4-vane resonant cavity designed at the frequency of 352.21 MHz frequency. It must accelerate and bunch a 70 mA proton beams from 75 keV to 3.62 Mev of energy with a 4% duty cycle. The current 3D design evolved and is currently divided in 5 segments for a total length of 4.54 m. This paper presents a complete radiofrequency (RF) analysis using the ANSYS Multiphysics 3D RF simulating code HFSS and a RFQ 4-wire transmission line model (TLM). It describes the integrated cooling strategy based on a coupling between the RF power losses and the thermo-mechanical physics in order to allow a proper RFQ tuning once under operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR054  
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THPLR055
 Tuning of the CERN 750 MHz RFQ for Medical Applications  
THOP09   use link to access more material from this paper's primary paper code  
 
  • B. Koubek, Y. Cuvet, A. Grudiev, C. Rossi, M.A. Timmins
    CERN, Geneva, Switzerland
  
  CERN has built a compact 750 MHz RFQ as an injector for a hadron therapy linac. This RFQ was designed to accelerate protons to an energy of 5 MeV within only 2 m length. It is divided into four segments and equipped with 32 tuners in total. The RFQ length corresponds to 5λ which is considered to be close to the limit for simple field adjustment using tuners. Nevertheless the high frequency results in a sensitive structure and requires careful tuning by means of the alignment of the pumping ports and fixed tuners. This paper gives an overview of the tuning procedure and bead pull measurements of the RFQ.  
slides icon Slides THPLR055 [16.367 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP09  
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THPLR056
 Beam Commissioning of the i-BNCT Linac  
THOP08   use link to access more material from this paper's primary paper code  
 
  • F. Naito, S. Anami, Z. Fang, K. Futatsukawa, Y. Honda, Y. Hori, M. Kawamura, H. Kobayashi, T. Kurihara, T. Miura, T. Miura, T. Miyajima, T. Obina, F. Qiu, Y. Sato, T. Shibata, M. Shimamoto, A. Takagi, E. Takasaki, M. Uota
    KEK, Ibaraki, Japan
  • S. Fujikura
    ICEPP, Tokyo, Japan
  • K. Ikegami
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • H. Kumada, Su. Tanaka
    Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
  • Y. Liu, T. Maruta
    KEK/JAEA, Ibaraki-Ken, Japan
  • A. Miura
    JAEA/J-PARC, Tokai-mura, Japan
  • N. Nagura, T. Ohba
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  • T. Onishi
    Tsukuba University, Ibaraki, Japan
  • T. Ouchi
    ATOX, Ibaraki, Japan
  
  The beam commissioning of the linac for the boron neutron capture therapy of Ibaraki prefecture (i-BNCT) has been started. The accelerator of i-BNCT consists of the 3-MeV RFQ and 8-MeV DTL. The design of RF structure of them is based on the J-PARC linac. After the first demonstration of neutron production on December 2015, significant modifications to the linac were given in order to increase the operation stability and the beam power. The progress of the beam commissioning of the i-BNCT will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP08  
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THPLR058
 Novel Scheme to Tune RF Cavities Using Reflected Power  
SPWR034   use link to access more material from this paper's primary paper code  
THOP06   use link to access more material from this paper's primary paper code  
 
  • R. Leewe, K. Fong, Z. Shahriari
    TRIUMF, Vancouver, Canada
  • M. Moallem
    SFU, Surrey, Canada
  
  Tuning of the natural resonance frequency of an RF cavity is essential for accelerator structures to achieve efficient beam acceleration and to reduce power requirements. Typically operational cavities are tuned using phase comparison techniques. The phase measurement is subject to temperature drifts and renders this technique labor and time intensive. To eliminate the phase measurement, reduce human oversight and speed up the start-up time for each cavity, this paper presents a control scheme that relies solely on the reflected power measurements. A sliding mode extremum seeking algorithm is used to minimize the reflected power. To avoid tuning motor abrasion, a variable gain minimizes motor movement around the optimum operating point. The system has been tested and is fully commissioned on two drift tube linear accelerator tanks in TRIUMF's ISAC I linear accelerator. Experimental results show that the resonance frequency can be tuned to its optimum operating point while the start-up time of a single cavity and the accompanied human oversight are significantly decreased.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP06  
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THPLR059 Status of a 325 MHz High Gradient CH - Cavity 982
 
  • A. Almomani, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Funding: BMBF with contract number 05P12RFRB9
The reported linac developments aim on compact ion accelerators and on an increase of the effective accelerat-ing field (voltage gain per meter). Within a funded pro-ject, a high gradient Crossbar H-type CH-cavity operat-ed at 325 MHz was developed and successfully built at IAP-Frankfurt. The effective accelerating field for this cavity is expected to reach about 13.3 MV/m at a beam energy of 12.5 AMeV, corresponding to β=0.164. The results from this cavity might influence the later energy upgrade of the Unilac at GSI Darmstadt. The aim is a compact pulsed high current ion accelerator for significantly higher energies up to 200 AMeV. Detailed investigations for two different types of copper plating (high lustre and lustre less) with respect to the high spark limit will be performed on this cavity. The 325 MHz GSI 3 MW klystron test stand is best suited for these investigations. Additionally, operating of normal conducting cavities for the case of very short RF pulses will be discussed at cryogenic temperature. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR059  
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THPLR060 Experience with the Conditioning of Linac4 RF Cavities 985
 
  • S. Papadopoulos, F. Gerigk, J.-M. Giguet, J. Hansen, J. Marques Balula, A.I. Michet, S. Rambergerpresenter, N. Thaus, R. Wegner
    CERN, Geneva, Switzerland
  
  Linac4, the future H− injector of the PS complex at CERN has reached the hardware and beam commissioning phase. This paper summarizes the experience gained in RF conditioning of the DTL, CCDTL and PIMS cavities. The behaviour in conditioning of these cavities strongly depends on the cavity type and assembly conditions. Examples of conditioning history and vacuum measurements before, during and after conditioning are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR060  
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THPLR061 Research on a Two-beam Type Drift Tube Linac 989
 
  • L. Lu, C.X. Li, W. Ma, L.B. Shi, L.P. Sun, X.B. Xu, H.W. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  • T.L. He
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • L. Yang
    USTC, Hefei, Anhui, People's Republic of China
  
  The very high intense heavy-ion beam is a high attraction for heavy ion researches and heavy-ion applications, but it is limited by heavy-ion production of ion source and space-charge-effect in acceleration. There is one way, accelerating several heavy-ion beams in one cavity at same time and funneling them, which could achieve the acceleration of very high intense heavy-ion beam with existing ion source and accelerating technology. In this paper, we will introduce our designs, calculations and simulations of a 2-beam type drift tube linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR061  
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THPLR062 Muon Acceleration Using an RFQ 992
 
  • Y. Kondo, K. Hasegawa
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Fukao, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura
    KEK, Tsukuba, Japan
  • K. Ishida
    RIKEN Nishina Center, Wako, Japan
  • R. Kitamura
    University of Tokyo, Tokyo, Japan
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  A muon linac development for a new muon g-2 experiment is now going on at J-PARC. Muons from the muon beam line (H-line) at the J-PARC MLF are once stopped in an silica aerojel target and room temperature muoniums are evaporated from the aerogel. They are dissociated with laser (ultra slow muons), then accelerated up to 212 MeV using a linear accelerator. As the first accelerating structure, an RFQ will be used. We are planning to use a spare RFQ of the J-PARC linac for the first acceleration test. For this acceleration test, an degraded muon beam will be used instead of the ultra slow muon sourece. In this paper, present status of this muon acceleration test using the J-PARC RFQ is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR062  
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THPLR063 RF Design of a Deuteron Beam RFQ 996
SPWR020   use link to see paper's listing under its alternate paper code  
 
  • C.X. Li, W.P. Dou, Y. He, F.F. Wang, Z.J. Wang, X.B. Xu, Z.L. Zhang
    IMP/CAS, Lanzhou, People's Republic of China
  
  In a material irradiation facility in IMP, a RFQ is required for accelerating deuteron beam from 20 keV/u to 1.52 MeV/u. The structure design of the RFQ is drawing on the experience of the RFQ of Injector II of China ADS LINAC. Four-vane structure is adopted and the operation frequency is 162.5 MHz. Inter vane voltage is 65 kV and the Kilpatrick factor is 1.4. Π-mode stabilizing loops are used to move the dipole modes away from the working mode. Slug tuners are used to compensate for capacitance errors induced by machining. Cutbacks and end plate are modified to reach a reasonable field flatness. After the structure design and optimization, the simulation results of the cavity frequency is 162.459 MHz, the power loss is 109 kW. The multiphysics simulations are also performed to determine the frequency shift caused by the shift of the cooling water temperature.  
poster icon Poster THPLR063 [0.971 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR063  
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THPLR064 Design and Simulation of a High Intensity Heavy Ion RFQ Accelerator Injector 999
SPWR019   use link to see paper's listing under its alternate paper code  
 
  • W. Ma, Y. He, C.X. Li, L. Lu, L.B. Shi, L.P. Sun, X.B. Xu, Z.L. Zhang, H.W. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  
  An 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been developed for Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP), the Chinese Academy of Science (CAS). In the CW operating mode, the proposed RFQ design adopted the conventional four-vane structure. The main design goals are providing the high shunt impendence with low power losses. In the electromagnetic (EM) design, the π-mode stabilizing loops (PISLs) were optimized to produce a good mode separation. The tuners were also designed and optimized to tune frequency and field flatness of the operating mode. The vane undercuts were optimized to provide a flat field along the RFQ cavity. Additionally, a full length model with modulations was set up for the final EM simulations. In this paper, detailed EM design of the LEAF-RFQ will be presented and discussed. Meanwhile, structure error analysis is also studied.  
poster icon Poster THPLR064 [3.021 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR064  
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THPLR065 Beam Commissioning Status and Results of the FNAL PIP2IT Linear Accelerator RFQ 1002
 
  • J. Steimel, C.M. Baffes, P. Berrutti, J.-P. Carneiro, J.P. Edelen, T.N. Khabiboulline, L.R. Prost, V.E. Scarpine, A.V. Shemyakin
    Fermilab, Batavia, Illinois, USA
  • A.L. Edelen
    CSU, Fort Collins, Colorado, USA
  • M.D. Hoff, A.R. Lambert, D. Li, T.H. Luo, J.W. Staples, S.P. Virostek
    LBNL, Berkeley, California, USA
  • V.L. Sista
    BARC, Mumbai, India
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
An H− beam was accelerated through a continuous wave (CW) capable, 4-vane, radio frequency quadrupole (RFQ) at Fermilab that was designed and constructed at Berkeley Lab. This RFQ is designed to accelerate up to 10 mA H− beam from 30 keV to 2.1 MeV in a test accelerator (PIP2IT). This paper presents results of specification verification and commissioning. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR065  
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THPLR066 Preparation and Installation of IFMIF-EVEDA RFQ at Rokkasho Site 1005
 
  • E. Fagotti, L. Antoniazzi, A. Baldo, A. Battistello, P. Bottin, L. Ferrari, M.G. Giacchini, F. Grespanpresenter, M. Montis, A. Pisent, D. Scarpa
    INFN/LNL, Legnaro (PD), Italy
  • D. Agguiaro, A.G. Colombo, A. Pepato, L. Ramina
    INFN- Sez. di Padova, Padova, Italy
  • F. Borotto Dalla Vecchia, G. Dughera, G. Giraudo, E.A. Macri, P. Mereu, R. Panero
    INFN-Torino, Torino, Italy
  
  The IFMIF-EVEDA RFQ is composed of 18 modules for a total length of 9.8 m and is designed to accelerate the 125 mA D+ beam up to 5 MeV at the frequency of 175 MHz. The RFQ is subdivided into three Super-Modules of six modules each. The Super-Modules were pre-assembled, aligned and vacuum tested at INFN-LNL and then shipped to Rokkasho (Japan). At Rokkasho site a series of test were performed in order to verify the effect of the shipment on the cavity. The assembly debug, shipment equipment and the sequence of operations are described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR066  
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THPLR067 Series Production of the RF Power Distribution for the European XFEL 1008
 
  • S. Choroba, V.V. Katalev
    DESY, Hamburg, Germany
  • E.M. Apostolov
    Technical University of Sofia, Sofia, Bulgaria
  
  The RF power distribution for the European XFEL allows for individual RF power for the 808 superconducting cavities of the European XFEL. It consists of a number of elements, not only waveguide components, but also girders, cables or cooling systems. The production of the RF distribution consists of several tasks. In order to deal with the schedule of the entire project a detailed planning, organization and monitoring of the series production of the RF power distribution was required. This paper describes the RF power distribution layout and the series production process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR067  
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THPLR069 Quality Factor Measurement Method Using Multi Decay Time Constants on Cavity 1011
 
  • J.W. Kim, H. Kimpresenter
    IBS, Daejeon, Republic of Korea
  
  Quality factor measurement method using multi decay time constants on superconducting cavity is suggested. In most cases of vertical test, one decay time constant is measured around critical coupling and coupling constants are measured using forward and reflected rf power to get intrinsic quality factor. We use multi decay time constants method to measure the quality factor, which uses three decay time constants. Two more switches before and after the cavity are added to the measurement system. Decay time constants are measured by switching off the rf power switch in front of rf source, the forward power switch in front of input power coupler, and then the pickup power switch behind the pickup coupler, respectively, at the same power of steady state.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR069  
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THPLR071
 Ultra-Short Bunch Electron Injector for Awake  
THOP11   use link to access more material from this paper's primary paper code  
 
  • S. Döbert
    CERN, Geneva, Switzerland
  
  The proton driven plasma wake field acceleration experiment AWAKE at CERN will start at the end of this year. In 2017 an S-band electron injector producing bunches of a few ps length will be added to probe the wake fields stimulated by a driving proton beam. In the future this electron injector will have to be upgraded to obtain electron bunches with a length of 100 - 200 fs in order to demonstrate injection into a single bucket of the plasma wave and therefore sustainable acceleration with low energy spread. Target bunch parameters for the study are a bunch charge of 100 pC, 100 fs bunch length, an emittance smaller than 2 mm mrad and a beam energy of 100 MeV. The status of a study to achieve these parameters using X-band accelerator hardware and velocity bunching will be presented.  
slides icon Slides THPLR071 [2.733 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP11  
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THPLR072
 Electron Linac Upgrade for Thomx Project  
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  • L. Garolfi, C. Bruni, M. El Khaldi
    LAL, Orsay, France
  • N. Faure, A. Perez Delaume
    PMB-ALCEN, PEYNIER, France
  
  The injector Linac for Thomx * consists of an electron gun and S-band accelerating section. The RF gun is a 2.5 cells photo-injector able to provide electron bunches with 5 MeV energy. During the commissioning phase, a standard S-band accelerating section is able to achieve around 50 MeV corresponding to around 45 keV X-rays energy. Since the maximum targeted X-ray energy is 90 keV, the Linac design will provide a beam energy of 70 MeV. The Linac upgrade of the machine covers many different aspects. The purpose is to increase the compactness of the accelerator complex whereas the beam properties for ring injection are kept. A LAL Orsay-PMB ALCEN collaboration has been established. The program foresees the RF design, prototyping and power tests of a high-gradient compact S-band accelerating structure. To fulfill the technical specifications at the interaction point, the Linac must be carefully designed. Beam dynamics simulations have been performed for optimizing the emittance and the energy spread for the ring entrance. The best set of parameters together with the effect of the accelerating section to the beam dynamics at the end of the LINAC will be presented.
* A. Variola, et al, "The Thomx Project Status", Proceedings of IPAC2014, Dresden, Germany. 		 
slides icon Slides THPLR072 [1.726 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP12  
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THPLR074 N-Doped Niobium Accelerating Cavities: Analyzing Model Applicability 1014
 
  • R.G. Eichhorn, N.A. Stilin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • W. Weingarten
    CERN, Geneva, Switzerland
  
  So-called Nitrogen-doped cavities show a rather strange field dependent behavior of the surface resistance. We had come up with a rather straightforward two fluid model description of the Q-slope in the low and high field domains in an earlier publication based on one dataset of a cavity. In this contribution we report on successfully applying this model to other cavity performance data as well as cases were the model fails.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR074  
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