Keyword: resonance
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MOP082 Measurement of the Vibration Response of the EXFEL RF Coupler and Comparison With Simulated Data (Finite Element Analyses) FEL, cryomodule, acceleration, interface 273
 
  • S. Barbanotti, C. Engling, K. Jensch
    DESY, Hamburg, Germany
 
  The coupler is one of the main and most sensitive components of the European X-ray Free Electron Laser (EXFEL) superconducting cryomodule. More than 800 couplers were transported for more than 800 km assembled in a cryomodule during the assembly phase of the EXFEL without any visible damage. However, in a different project, a very similar coupler design showed a week point in one of the bellows when transported over a similar distance with a comparable transport set up. Therefore we decided to further study the coupler behaviour: we investigated the frequency response of the coupler on a vibration table in a controlled environment for different road and loading conditions and compared the data with simulated ones. This paper present the work performed so far and our conclusions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP082  
About • paper received ※ 18 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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TUP005 Cavity Designs for the CH3 to CH11 of the Superconducting Heavy Ion Accelerator HELIAC cavity, linac, heavy-ion, electron 396
 
  • T. Conrad, M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    KPH, Mainz, Germany
  • W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
 
  In collaboration of GSI, HIM and Goethe University Frankfurt new designs for the CH-DTL cavities of the proposed Helmholtz Linear Accelerator (HELIAC) are developed. The cw-mode operated linac with a final energy of 7.3 MeV/u is intended for various experiments, especially with heavy ions at energies near the coulomb barrier. Currently twelve superconducting CH-cavities are considered which will be split into four different cryostats. Each cavity will be equipped with dynamic bellow tuners. After successful beam tests with CH0 as well as last surface preparations and ongoing rf tests with CH1 and CH2, CH3 to CH11 will be designed. Based on the successful test results, individual optimizations are carried out on the cavity design. Attention was paid to reduce production costs, for example by keeping the cavity diameter in each cryostat constant despite varying particle velocities and gap numbers. In addition to reaching the resonance frequency of 216.816 MHz and the influence of the bellow tuners on the frequency, the mechanical stability of the bellow tuners, the thermal effects on the cavity and the measures to mitigate secondary electron emission are investigated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP005  
About • paper received ※ 19 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP032 Modal Analysis and Vibration Test for Quarter Wave Resonator for RAON cavity, cryomodule, SRF, controls 485
 
  • M.O. Hyun, H.C. Jung, Y. Kim, M. Lee
    IBS, Daejeon, Republic of Korea
 
  Funding: This paper was supported by the Rare Isotope Science Project (RISP), which is funded by the Ministry of Science and ICT (MSIT) and National Research Foundation (NRF) of the Republic of Korea.
The Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS), Korea, is developing and con-structing the multi-purpose linear accelerator at the north side of Daejeon, South Korea. RISP accelerator (RAON) is composed with low-energy region (SCL3) and high-energy region (SCL2), and low-energy region is made with quarter-wave resonator (QWR) and half-wave resonator (HWR) when high-energy region is made with single spoke resonator type-1 (SSR1) and type-2 (SSR2). This paper shows about the initial resonance issues of QWR superconducting (SC) cavity during cold test and SRF disturbance measurement. Afterwards, this paper shows the modal analysis and vibration test of QWR SC cavity.
 
poster icon Poster TUP032 [0.584 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP032  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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TUP083 Performance of the 650 MHz SRF Cavity Tuner for PIP II Project cavity, SRF, cryomodule, interface 652
 
  • Y.M. Pischalnikov, S.K. Chandrasekaran, S. Cheban, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
 
  The PIP-II linac will include fifty seven 650MHz SRF cavities. Each cavity will be equipped with tuner for coarse and fine frequency tuning. Design and operations parameters will be discussed. Results from room temperature tests with prototype tuner installed on a 650MHz ’G=0.90 elliptical cavity will be presented.  
poster icon Poster TUP083 [1.567 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP083  
About • paper received ※ 23 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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TUP085 Operation of an SRF Cavity Tuner Submerged into Liquid He cavity, experiment, SRF, operation 660
 
  • Y.M. Pischalnikov, D.J. Bice, A. Grassellino, T.N. Khabiboulline, O.S. Melnychuk, R.V. Pilipenko, S. Posen, O.V. Pronitchev, A.S. Romanenko
    Fermilab, Batavia, Illinois, USA
 
  To precisely control the resonance of 1.3 GHz SRF cavities during testing at the FNAL’s Vertical Test Facility, we install for the first time a double lever tuner and operate it when submerged into the liquid He bath. Both active components of the tuner: electromechanical actuator (stepper motor) and piezo-actuators are operated inside superfluid helium. Accuracy in controlling the SRF cavity resonance frequency will be presented. Specifics of the tuner operation when submerged into liquid He will be discussed.  
poster icon Poster TUP085 [2.164 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP085  
About • paper received ※ 23 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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WETEB6 Active Suppression of Microphonics Detuning in High QL Cavities cavity, controls, linac, SRF 776
 
  • N. Banerjee, G.H. Hoffstaetter, M. Liepe, P. Quigley
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA). SRF 2019 provided travel support in the form of a student grant.
Accelerators operating with low beam loading such as Energy Recovery Linacs (ERL) greatly benefit from using SRF cavities operated at high loaded quality factors, since it leads to lower RF power requirements. However, large microphonics detuning several times the operating bandwidth of the cavities severely limit the maximum accelerating fields which can be sustained in a stable manner. In this talk, I will describe an active microphonics control technique based on the narrow band Active noise Control (ANC) algorithm which we have used in CBETA, a multi-turn SRF ERL being commissioned at Cornell University. I will describe its stability and performance during beam operations of CBETA with consistent reduction of peak detuning by almost a factor of 2 on multiple cavities.
 
slides icon Slides WETEB6 [10.296 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB6  
About • paper received ※ 23 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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THP074 Microphonics Noise Suppression with Observer Based Feedback cavity, controls, SRF, linac 1068
 
  • M. Keikha, K. Fong
    TRIUMF, Vancouver, Canada
  • M. Moallem
    SFU, Surrey, Canada
 
  Funding: TRIUMF
Detuning of superconducting radio frequency (SRF) cavities is mainly caused by the Lorentz force, which is the radiation pressure induced by a high radio frequency (RF) field, and environmental mechanical vibrations that induce undesirable interference signals referred to as microphonics. Both of these influences can be described by a second order differential equation of the mechanical vibration modes of the cavity. In this paper we consider three dominant mechanical modes of the system and develop a control scheme based on input-output linearization. It is shown through simulation studies that the proposed control technique can successfully the suppress microphonic noise due to the SRF cavity’s dynamics.
 
poster icon Poster THP074 [0.610 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP074  
About • paper received ※ 22 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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