Author: Zheng, H.J.
Paper Title Page
TUP080 Tuner Design and Test for 166.6 MHz SRF Cavity of HEPS 642
 
  • Z.H. Mi, Z.Q. Li, H.Y. Lin, W.M. Pan, Q.Y. Wang, P. Zhang, X.Y. Zhang, H.J. Zheng
    IHEP, Beijing, People’s Republic of China
 
  The 166.6 MHz superconducting RF cavities have been proposed for the High Energy Photon Source (HEPS), a 6 GeV kilometer-scale light source. The cavity is of quarter-wave type made of bulk niobium with ’=1. Each cavity will be operated at 4.2 K providing 1.2 MV accelerating. To compensate the frequency change due to manufacturing uncertainty, Lorentz force, beam loading, He pressure and microphonics the plunger tuner and gap tuner are chosen as options. Now the plunger tuner and low temperature gap tuner have been test with cavity, while the warm gap tuner is being designed. Details of the design and summary of the test results of the two type tuners with cavity are presented in this paper.  
poster icon Poster TUP080 [1.141 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP080  
About • paper received ※ 22 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP070 CEPC HOM Coupler R&D 1050
 
  • H.J. Zheng, F. Meng, P. Sha, J.Y. Zhai
    IHEP, Beijing, People’s Republic of China
 
  The conceptual design report (CDR) for the Circular Electron Positron Collider (CEPC) has been published in September 2018. In this talk, the CDR design and prototyping of the HOM coupler for the CEPC Collider ring cavity will be given. Each cavity has two detachable coaxial HOM couplers mounted on the cavity beam pipe with HOM power handling capacity of 1 kW. A double notch coupler is chosen due to its wide bandwidth for the fundamental mode. A prototype of this HOM coupler and a coaxial line test bench have been fabricated and tested under low power. The low power test results agree well with the simulation results. The high power test was also carried out in room temperature.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP070  
About • paper received ※ 19 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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THP071 HOM Measurement Results for CEPC 650 MHz 2-cell Cavity 1055
 
  • H.J. Zheng, F. Meng, J.Y. Zhai
    IHEP, Beijing, People’s Republic of China
 
  CEPC will use a 650 MHz RF system with 240 2-cell cavities for the Collider. The Collider is a double-ring with shared cavities for Higgs operation and separate cavities for W and Z operations. The higher order modes (HOM) excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. In this paper, the impedance budget and HOM damping and HOM power requirement for the CEPC Collider ring are given. This HOM power limit and the fast-growing longitudinal coupled-bunch instabilities (CBI) driven by both the fundamental and higher order modes impedance of the RF cavities determine to a large extent the highest beam current and luminosity obtainable in the Z mode. Two prototypes of HOM coupler have been fabricated and installed on the 650 MHz 2-cell cavity. The higher order modes were verified by bead pulling method. The Qe for the HOMs were also measured. A test bench with two 2-cell cavities was used to measure the real damping results and HOM propagating properties for a cavity string.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP071  
About • paper received ※ 19 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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FRCAA5
SRF Activities and Progress at IHEP  
 
  • F.S. He, F. Bing, J. Dai, C. Dong, T.M. Huang, S. Jin, D.B. Li, Z.Q. Li, H.Y. Lin, B.Q. Liu, Z.C. Liu, Q. Ma, F. Meng, Z.H. Mi, W.M. Pan, P. Sha, Q.Y. Wang, L.G. Xiao, F.Y. Yang, J.Y. Zhai, P. Zhang, X.Y. Zhang, H.J. Zheng, Q. Zhou
    IHEP, Beijing, People’s Republic of China
 
  There are several active SRF projects at IHEP, including HEPS, CEPC, CSNS upgrade, SHINE and PAPS SRF facility. Four cryomodules with 166.6 MHz β=1 QWR cavities are proposed for HEPS, while each cavity will providing 1.2 MV and 145 kW to the electron beam. The vertical and horizotal tests of the proof-of-principle cavities were recently conducted. 650 MHz 2-cell cavities and 1.3 GHz 9-cell cavities were proposed for the CEPC, and high Q technology is adopted by the project. Infrastructures are developed for the high Q study, while R&D on single-cell cavities are under-way. Efforts on learning mass-production of cavities and cavity-string were also made for both CEPC and SHINE projects. SRF linac from 80 MeV to over 300 MeV were adopted for the upgrade of CSNS, with 325 MHz Double-spoke cavities at β=0.50 and 650 MHz-5cell elliptical cavities at β=0.65. The PAPS SRF facility is biased on mass production for large SRF projects, i.e. aiming at assembly and testing of 200-400 cavities & couplers and 20 cryomodules per year. The equipment installation and commissioning is on going. The activities and progress of these SRF projects with be addressed in this presentation.  
slides icon Slides FRCAA5 [13.318 MB]  
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