Keyword: resonance
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MOPO006 Crosstalk Effect in the LEReC Booster Cavity cavity, booster, HOM, cathode 47
 
  • B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
The Linac of Low Energy RHIC electron Cooler (LEReC) is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with peak-to-peak dp/p less than 7·10-4. The booster cavity is the major accelerating component in LEReC, which is a 0.4 cell cavity operating at 2 K, with a maximum energy gain of 2.2 MeV. It is modified from the Energy Recovery Linac (ERL) photocathode gun, with fundamental power coupler, pickup coupler and HOM coupler close to each other. Crosstalk effect in this cavity is simulated and measured. Correction method is proposed to meet the energy spread requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO006  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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MOPO026 The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac cavity, controls, electron, coupling 81
 
  • M. Mohseni Kejani, F. Abbasi Davani
    Shahid Beheshti University, Tehran, Iran
  • S. Ahmadiannamin
    ILSF, Tehran, Iran
  • F. Ghasemi
    NSTRI, Tehran, Iran
  • S. Zarei
    Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
 
  A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO090 Measurements of the First Room Temperature CH Cavity for MYRRHA at IAP Frankfurt cavity, simulation, status, rfq 193
 
  • K. Kümpel, S. Lamprecht, P. Müller, N.F. Petry, H. Podlech, S. Zimmermann
    IAP, Frankfurt am Main, Germany
 
  Funding: This work has been supported by MYRTE which is funded by the European Commission under Project-ID 662186.
The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is a planned accelerator driven system (ADS) for the transmutation of long-living radioactive waste. A critical passage for the beam quality and especially for the emittance is the injector, which for the MYRRHA project consists of a 4-Rod RFQ, two Quarter Wave Rebunchers (QWR) and a total of 16 normal conducting CH-DTL cavities. The first installment of the MYRRHA injector in Louvein-La-Neuve (Belgium) will include an ion source, a RFQ, the QWRs and the first seven CH DTL cavities. This paper will report on the status of the low level tests on CHs 1 and 2 as well as on further developments on CHs 8-15.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO090  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO104 LLRF R&D Towards CW Operation of the European XFEL FEL, cavity, controls, LLRF 223
 
  • A. Bellandi, V. Ayvazyan, J. Branlard, C. Gumus, S. Pfeiffer, K.P. Przygoda, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
 
  The ever growing request for machines with a higher average beam pulse rate and also with a relaxed (< 1 MHz) pulse separation calls for superconducting linacs that operate in Long Pulse (LP) or Continuous Wave (CW) mode. For this purpose the European X-ray Free Electron Laser (European XFEL) could be upgraded to add the ability to run in CW/LP mode. Cryo Module Test Bench (CMTB) is a facility used to perform tests on superconducting cavity cryomodules. Because of the interest in upgrading European XFEL to a CW machine, CMTB is now used to perform studies on XM-3, a 1.3 GHz European XFEL-like cryomodule with modified coupling that is able to run with very high quality factor (QL = 10E7…10E8) values. The RF power source allows running the cavities at gradients larger than 16 MV/m. Because of the QL and gradient values involved in these tests, detuning effects like mechanical resonances and microphonics became more challenging to regulate. The goal is then to determine the appropriate set of parameters for the LLRF control system to keep the error to be less than 0.01° in phase and 0.01% in amplitude.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO104  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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TUPO052 Design Study of a Prototype 325MHz RF Power Coupler for Superconducting Cavity simulation, cavity, pick-up, superconducting-cavity 451
 
  • J.Y. Yoon, J.B. Bhang, H.J. Cha, S.W. Jang, E.-S. Kim, K.R. Kim, C.S. Park, S. H. Park
    Korea University Sejong Campus, Sejong, Republic of Korea
  • E. Kako
    KEK, Ibaraki, Japan
  • D.Y. Kim, J. Lee
    Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea
  • I. Shin
    IBS, Daejeon, Republic of Korea
 
  Funding: Korea University (Sejong Campus) in South KOREA
We present design studies of a prototype RF input power coupler, which provides RF powers to 325MHz cavities up to 18.5 kW in CW mode. The prototype power coupler is a coaxial capacitive type with single ceramic window. In order to optimize the RF coupler design, we performed multi-physics simulations, including electromagnetic, thermal, and mechanical analyses.
 
poster icon Poster TUPO052 [1.607 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO052  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO058 Cool Down Studies for the LCLS-II Project cavity, network, SRF, linac 470
 
  • M. Ge, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • D. Gonnella
    SLAC, Menlo Park, California, USA
  • J. Sears
    Cornell University, Ithaca, New York, USA
 
  The quality factor of the nitrogen-doped SRF cavities for the LCLS-II project are strongly impacted by cool down speed. A sufficiently fast cool down speed can produce large thermal gradient across a cavity and sufficiently expel magnetic flux when the cavity wall passes from the normal-conducting to the superconducting state. However, instrumentation in LCLS-II production cryomodules has been kept at a minimum, and additional information during the cool down of the modules is therefore desirable. In this work, we study if and how RF data can be used during cavity cool-down to determine the transition speeds of the individual cavities in the LCLS-II linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO058  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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THPO020 Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator electron, SRF, GUI, acceleration 725
 
  • Y.T. Yuan
    HUST, Wuhan, People’s Republic of China
  • K. Fan
    Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
  • Y. Jiang
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
 
  Funding: the National Natural Science Foundation of China
The cyclotron auto-resonance accelerator (CARA) is a novel concept of accelerating continuous gyrating charged-particle beams to moderately or highly relativistic energies, which can be used as the high power microwave source and applied in environment improvement area, particularly in the flue gas pollution remediation. In CARA, the continuous-wave (CW) electron beam follows a gyrating trajectory while undergoing the interaction with the rotating TE-mode rf field and tapered static magnetic field. In the process of gyrating acceleration, the phase synchronization with the rf field is automatically maintained, so to speak, with auto-resonance. Simulation models are constructed to study the effect of rf field and static magnetic field on electron beam in CARA, where the beam energy, trajectory and velocity component are analysed. The simulation results match reasonably well with theoretical predication, which sets up a solid foundation for future designs of CARA.
 
poster icon Poster THPO020 [1.448 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO020  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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THPO045 Tuning Esperience on the ESS DTL Cold Model DTL, cavity, interface, alignment 784
 
  • F. Grespan, A. Baldo, P. Bottin, G.S. Mauro, A. Palmieri, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • P. Mereu, M. Mezzano
    INFN-Torino, Torino, Italy
 
  An aluminum model of the ESS DTL tank 2 has been delivered to INFN-LNL in december 2017. The tank is 7.1 m long, equipped with movable tuners and movable post couplers. The purpose of this DTL model is to verify the RF design choices (in particular on the first 2 tanks where the Post coupler distribution is irregular) as well as implement and debug algorithms and procedure for stabilization and tuning. The preparatory simulation work and the results of measurements campaign are here presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO045  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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