Keyword: superconducting-cavity
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SUPCAV010 Design of Third-Harmonic Superconducting Cavity for Shen-Zhen Industry Synchrotyon Radiation Source7 cavity, acceleration, accelerating-gradient, electron 32
  • N. Yuan, L. Lu, W. Ma
    Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China
  • G.M. Liu
    SINAP, Shanghai, People’s Republic of China
  • L. Yang, Z. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  Shenzhen industry synchrotron radiation source is the fourth generation of medium energy light source with beam energy of 3GeV. It has the characteristics of low emittance and high brightness. In the design, the beam lifetime is one of the most important parameters. The main factor that affects its beam lifetime is the scattering of electron collisions inside the beam. To solve this problem, a harmonic radio frequency system is used. The third harmonic superconducting elliptical cavity is de-signed to stretch beam length to improve beam quality and beam lifetime. The present work is mainly about the shape optimization of 1.5 GHz 2-cell third harmonic superconducting elliptical cavity. Firstly, the principle of harmonic cavity in dual high frequency system is introduced, and the resonant frequency and acceleration gradient of superconducting cavity are given. Then, CST, electromagnetic field simulation software is used to optimize the cavity parameters to obtain the high performance and high frequency parameters that meet the requirements.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPCAV010  
About • Received ※ 21 June 2021 — Revised ※ 21 November 2021 — Accepted ※ 18 February 2022 — Issue date ※ 03 May 2022
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SUPCAV014 Design and Simulation of 500 MHz Single Cell Superconducting Cavity cavity, HOM, simulation, ECR 46
  • Y.B. Sun, W. Ma
    Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China
  • G.M. Liu
    SSRF, Shanghai, People’s Republic of China
  • L. Lu, L. Yang, Z. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  Funding: Work supported by Shenzhen Development and Reform Commis-sion
The Shenzhen Industrial Synchrotron Radiation Light Source is a fourth-generation medium-energy light source with a 3GeV storage ring electron energy and an emit-tance less than 100 pm·rad. In order to ensure the long-term stable and efficient operation of the light source, a new type of 500 MHz single-cell superconducting cavity was designed in this study to be used as a pre-research superconducting cavity for the Light Source. The 500 MHz superconducting cavity has a large beam aperture and low high order modes (HOMs) impedance, which can be used in accelerators with larger currents. In this design, we simply adopted the same design scheme as the KEKB-type and CESR-type superconducting cavity. Using CST electromagnetic field simulation software to calculate and simulate the characteristics of the cavity, the results show that the designed 500 MHz single-cell cavity can meet the requirements of a high acceleration gradient, a high r/Q value, and a low peak surface field.
poster icon Poster SUPCAV014 [0.425 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPCAV014  
About • Received ※ 21 June 2021 — Revised ※ 07 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 05 May 2022
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MOPCAV010 Design of a HOM-Damped 166.6 MHz Compact Quarter-Wave β=1 Superconducting Cavity for High Energy Photon Source cavity, HOM, photon, impedance 278
  • X.Y. Zhang, J. Dai, L. Guo, T.M. Huang, Z.Q. Li, Q. Ma, F. Meng, Z.H. Mi, P. Zhang, H.J. Zheng
    IHEP, Beijing, People’s Republic of China
  Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
Superconducting cavities with low RF frequencies and heavy damping of higher order modes (HOM) are desired for the main accelerator of High Energy Photon Source (HEPS), a 6 GeV synchrotron light source promising ultralow emittance currently under construction in Beijing. A compact 166.6 MHz superconducting cavity was proposed adopting a quarter-wave β=1 geometry. Based on the successful development of a proof-of-principle cavity, a HOM-damped 166.6 MHz compact superconducting cavity was subsequently designed. Ferrite damper was installed on the beam pipe to reduce HOM impedance below stringent threshold of coupled-bunch instabilities. Being compact, RF field heating on the cavity vacuum seal was carefully examined against quenching the NbTi flange. The cavity was later dressed with helium vessel and the tuning mechanism was also realized. Excellent RF and mechanical properties were eventually achieved. Finally, the two-cavity string was designed to ensure smooth transitions among components and proper shielding of synchrotron light. This paper presents a complete design of a fully dressed HOM-damped low-frequency β=1 superconducting cavity for HEPS.
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPCAV010  
About • Received ※ 20 June 2021 — Accepted ※ 21 August 2021 — Issue date ※ 14 April 2022  
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MOPFDV002 High Density Mapping Sytems for SRF Cavities cavity, SRF, cryogenics, experiment 323
  • Y. Fuwa
    JAEA/J-PARC, Tokai-mura, Japan
  • R.L. Geng
    JLab, Newport News, Virginia, USA
  • H. Hayano
    KEK, Ibaraki, Japan
  • Y. Iwashita, Y. Kuriyama
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  High density mapping systems for superconducting cavities are prepared. They include sX-map, XT-map and B-map. Each strip of the sX-map system has 32 X-ray sensors approximately 10 mm apart, which can be installed under the stiffener rings to show uniform higher sensitivities. This is suitable to get X-ray distribution around iris areas. The XT-map system enables temperature distribution mapping of cavity cells with high spatial resolution at approximately 10 mm intervals in both azimuth and latitude. It also gives X-ray distribution on cells, as well. Magnetic field distributions can be obtained by B-map system using AMR sensors. Since all these systems are based on the technology of multiplexing at cryogenic side, less number of wires can carry the huge number of signals. The systems are described.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPFDV002  
About • Received ※ 02 July 2021 — Revised ※ 19 December 2021 — Accepted ※ 22 January 2022 — Issue date ※ 02 May 2022
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TUPCAV009 AMR Sensors Studies and Development for Cavities Tests Magnetometry at CEA cavity, SRF, cryogenics, detector 457
  • J. Plouin, E. Cenni, L. Maurice
    CEA-DRF-IRFU, France
  Studying flux expulsion during superconducting cavities test increases the need for exhaustive magnetometric cartography. The use of Anistropic Magneto Resistance (AMR) sensors, much cheaper than commercial fluxgates, allows the use of tens of sensors simultaneously. Such sensors are developed and sold for room temperature application but are resistant to cryogenic temperatures. However, they need proper calibration, which is more difficult at cryogenic temperature. Actually, this calibration uses the flip of the magnetization of the anisotropic ferromagnetic element, which coercitive field is increased at low temperature. We will present the development of method and software carried out at CEA for the use of such sensors, as well as the preliminary design of a rotating magnetometric device destined to elliptical cavities.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPCAV009  
About • Received ※ 22 June 2021 — Revised ※ 13 January 2022 — Accepted ※ 22 February 2022 — Issue date ※ 22 February 2022
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WEPFDV005 Tensile Tests of Large Grain Ingot Niobium at Liquid Helium Temperature niobium, cavity, experiment, SRF 562
  • M. Yamanaka
    KEK, Ibaraki, Japan
  • K. Enami
    Tsukuba University, Ibaraki, Japan
  Tensile tests at liquid He temperature were performed using specimen taken from high purity large grain niobium ingot produced by CBMM. The measured RRR is 242. The ingot is 260 mm in diameter and sliced by a multi wire saw to 2.8 thickness. 5 specimens were cut off from one sliced disk. 3 disks were set in same phase to obtain same grain distribution. 3 specimens each of 5 grain patterns 5, 15 in total were used for the tensile test. The tensile test stand using a cryostat and liquid He was manufactured by ourselves. The measured tensile strength varied 379 to 808 MPa. The average value is 611 MPa. The tensile strength at room temperature is 84 MPa. The strength becomes high at low temperature like a fine grain niobium. The specimen includes a grain boundary, and causes the variation of strength. The different result was obtained in same grain patterns. The relationship between crystal orientation and strength is discussed.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPFDV005  
About • Received ※ 08 June 2021 — Accepted ※ 12 September 2021 — Issue date ※ 02 May 2022  
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