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MOOCA03 Design of High-power Graphene Beam Window scattering, proton, emittance, target 45
 
  • H.J. Wang, H.T. Jing, H. Qu, J.Y. Tang
    IHEP, Beijing, People's Republic of China
 
  Beam window is a key device in high-intensity hadron beam applications, and it is usually used to separate air or other gas environments in the end of beam vacuum duct. Compared with the usually-used window materials such as Inconel alloy, Aluminum alloy and so on, the graphene has extremely high thermal conductivity, high strength and high transparency to high-energy ions. With the maturation of large-size graphene manufacturing technology, we have studied this new-type window for MW-class proton beam. The thermal analyses by the theoretical formula and simulations based on FEA are presented in this paper. Simultaneously, the scattering effect and the lifetime are also discussed. The preliminary results are promising. The same material can also be possibly applied to other devices such as charge-exchange stripping foils, beam monitors and so on.  
slides icon Slides MOOCA03 [1.467 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCA03  
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MOPRI041 Electrons Injectors with Cathode Diameter of 6/15mm and New Cup Energy Input on the Wave E11 for Accelerators cathode, electron, gun, target 692
 
  • K.G. Simonov, E.A. Alkhimenko, T.A. Batkova, S.I. Grishin, A.V. Mamontov, G.I. Pravdikovskaya, E.A. Stroykov
    ISTOK, Moscow Region, Russia
  • A.I. Shapovalov
    MRTI RAS, Moscow, Russia
 
  RPC "Istok" has created a number of electron injectors with voltage of 20-60kV and cathode diameter of 6-15mm of diode and triode designs. Injectors use the impregnated cathodes; the injector design allows rapid replacement of cathode assemblies. Injectors have been widely used in linear electron accelerators in Russia and Ukraine, in particular, in the sterilization accelerator center of JSC "MRTI RAS", Moscow, in the accelerator of the Russian Eye and Plastic Surgery Centre, Ufa. Have been proposed new input energy windows on the E11 wave, providing significant levels of transmission of the pulse power at high average power levels. Have been created two types of windows at 10-cm range, in which the ceramic disk made of ecologically clean alumina ceramic with diameter of 103mm and thickness of 13mm is used. In the first type of windows the heat transfer is provided from the peripheral portion, and in the second type of window – both from peripheral and central portions of the ceramic disk. These windows are used in accelerator of FSUE "NIIEFA" (St.Petersburg), installed at Izhora mill for testing the welding seals of atomic reactors and in accelerator of JSC "MRTI RAS".  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI041  
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TUPME074 First Experiences with the PITZ Plasma Cell for Electron Beam Self-modulation Studies plasma, electron, experiment, proton 1525
 
  • M. Groß, A. Donat, J.D. Good, M. Khojoyan, G. Koss, M. Krasilnikov, R. Schütze, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • R. Brinkmann
    DESY, Hamburg, Germany
  • F.J. Grüner, G. Pathak
    Uni HH, Hamburg, Germany
  • P. Muggli, E. Öz
    MPI-P, München, Germany
  • D. Richter
    HZB, Berlin, Germany
  • C.B. Schroeder
    LBNL, Berkeley, California, USA
 
  The self-modulation of long particle beams in a plasma has recently gained interest in light of the ongoing preparation for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN. Instrumental to the experiment is the self-modulation of a proton beam to generate bunches short enough for producing high acceleration fields. As electron bunches are easier to handle and the underlying physics is identical, it is judicious to first gain insight into the experimental conditions of the self-modulation of long particle beams in plasma by using electron bunches before progressing to the experiment with proton bunches. The experimental demonstration of self-modulation of an electron bunch is in preparation at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). In this contribution the fabrication and first experimental tests towards a Lithium plasma cell are highlighted. The distinctive feature of this plasma cell is the addition of side ports for insertion of the ionization laser beam and for diagnostics purposes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME074  
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WEPRI068 Conceptual Design of an Ideal Variable Coupler for Superconducting Radiofrequency 1.3 GHz Cavities cavity, vacuum, scattering, coupling 2648
 
  • C. Xu, S.G. Tantawi
    SLAC, Menlo Park, California, USA
 
  We present a new type of fundamental mode accelerator structure coupler. This coupler has a very simplified mechanical structure and is equipped with a novel vacuum window structure that allows the coupler to be divided into two parts. These two parts are fully thermally isolated, only coupled by thermal radiation. The rf power on the other hand get coupled perfectly from one part to the other. This is truly novel approach which is quite different than the conventional approach to this problem such as chock structure. The structure in general is slightly overmoded. We show that this structure can also be adopted to change the coupling coefficient and thus be tuned for an external Q. This could be of great utility for CW operation. We show the analytical and numerical calculation for a two window variable coupler.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI068  
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WEPRI072 High Power Co-axial Couplers for SRF Cavities klystron, SRF, simulation, network 2657
 
  • J. Guo, J. Henry, R.A. Rimmer, H. Wang, R.S. Williams
    JLab, Newport News, Virginia, USA
  • A. Dudas, M.L. Neubauer
    Muons, Inc, Illinois, USA
 
  Funding: Work supported by Dept. of Energy grant no. DE-SC0002769
High Power RF couplers are required in a wide range of accelerator projects using superconducting RF cavities. We have proposed a novel robust coax SRF coupler design using two pre-stressed disc windows without the need of additional matching elements. The matching frequency and the power handling capacity can be easily scaled by changing the diameter and the spacing of the windows. In this paper, we will present our latest progress in the fabrication and the testing of the windows.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI072  
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THPME030 Beam Dynamics and Accelerating Cavity Electrodynamics' Simulation of CW 2 MeV Proton RFQ rfq, linac, cavity, simulation 3286
 
  • S.M. Polozov, A.E. Aksentyev, T. Kulevoy
    MEPhI, Moscow, Russia
 
  The CW proton linac has a number of important applications; serving as the initial part of a high-energy, high-power linac for an accelerator-driven system is the main of them. Its CW operation mode and a 5-10 mA beam current, however, are limiting factors for the accelerating field. The surface field should not exceed the Kilpatrick field by more than 1.2-1.5 times. This limitation leads to the increase in linac length and beam bunching complexity. The first results of a 2 MeV, 5 mA, CW RFQ, designed for the operating frequency of 162 MHz, are discussed. Beam dynamics simulation results, obtained by using the BEAMDULAC-RFQ code*, are presented. The electrodynamics of the accelerating structure based on the four-vane cavity is discussed. The accelerating cavity design uses coupling windows as was proposed earlier **, but with windows of an elliptical form. Such form allows for better separation of quarupole and dipole modes.
* S.M. Polozov. Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 3 (79), 2012, p. 131-136.
** V.A. Andreev. Patent US5483130, 1996.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME030  
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THPME037 Development of a 72.75 MHz RFQ for the LINCE Accelerator Complex rfq, quadrupole, simulation, resonance 3304
 
  • A.K. Orduz, C. Bonțoiu, I. Martel, A.C.C. Villari
    University of Huelva, Huelva, Spain
  • A. Garbayo
    AVS, Elgoibar, Spain
  • P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  • A.C.C. Villari
    FRIB, East Lansing, Michigan, USA
 
  Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA.
Low-energy acceleration for the LINCE project [1] will be achieved using a 72.75 MHz normal conducting four vanes RFQ designed to give a 460 keV/u boost for A/Q = 7 ions in about 5 m. The vanes are modeled to accommodate windows for a clear separation of the RFQ modes and easy fitting to an octagonal resonance chamber. This article presents the main numerical results of the radio-frequency modeling and computational fluid dynamics (CFD). Particle tracking studies optimized for bunching and acceleration are shown as well.
[1] I. Martel et al., “LINCE: A High Intensity Multi-ion Superconducting Linac for Nuclear Structure and Reactions”, IPAC’14, Dresden, Germany, June 2014, THPME036, These Proceedings.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME037  
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THPME054 RF Cavity Design Aspects for a Helical Muon Beam Cooling Channel cavity, embedded, factory, collider 3352
 
  • F. Marhauser, G. Flanagan, R.P. Johnson, S.A. Kahn
    Muons, Inc, Illinois, USA
  • K. Yonehara
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported under U.S. DOE Grant Application Number DE-SC0006266
A Helical Cooling Channel (HCC) promises efficient six-dimensional ionization cooling of muon beams by utilizing high-pressurized gas as a continuous absorber within a magnetic channel embedding RF cavities. The progress on cavity design, tailored for such a cooling channel, is discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME054  
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THPME136 Beam Energy and Longitudinal Beam Profile Measurement System at RIBF LabView, controls, heavy-ion, ion 3566
 
  • T. Watanabe, M. Fujimaki, N. Fukunishi, H. Imao, O. Kamigaito, M. Kase, M. Komiyama, N. Sakamoto, K. Suda, M. Wakasugi, K. Yamada
    RIKEN Nishina Center, Wako, Japan
 
  Monitors that use plastic scintillator (scintillation monitors) were fabricated to measure the energy and longitudinal profiles of heavy-ion beams at the RIKEN RI beam factory (RIBF).Six pairs of scintillation monitors (12 monitors) installed in the transport lines were used to measure the particle time-of-flight (TOF) to determine the acceleration energy of the heavy-ion beams. In addition, five scintillation monitors were installed to optimize the phase between the rebuncher cavities and the beam for the beam injection to the cyclotrons. Longitudinal beam profiles were obtained by using a time-to-digital converter (TDC), which digitizes the detected signals from the scintillator and the RF clock. The energy of the beam can be calculated from the measured TOF of the beam by using a scintillation monitor pair. Recently, to help users operate the system more easily, a new embedded processor with a higher-performance CPU was introduced, and LabVIEW programs were newly written or greatly improved. Development of the scintillation monitor system and results of experimental measurements of heavy-ion beams are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME136  
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THPRI028 Acoustic Spark Localization for the 201 MHz RF Cavity cavity, experiment, vacuum, software 3828
 
  • P.G. Lane, Y. Torun
    Illinois Institute of Technology, Chicago, Illinois, USA
  • E. Behnke, I.Y. Levine
    Indiana University South Bend, South Bend, USA
  • D.W. Peterson
    Fermilab, Batavia, Illinois, USA
  • P. Snopok
    IIT, Chicago, Illinois, USA
 
  Funding: Work supported by U.S. Department of Energy
Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on the experiment setup for localizing sparks in an RF cavity by using piezoelectric transducers and on preparation for data collection on a 201.25 MHz vacuum cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI028  
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