Keyword: luminosity
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MOIXA05 Operating Experience of SRF System at High Beam Current in SuperKEKB cavity, operation, HOM, SRF 38
 
  • M. Nishiwaki, K. Akai, T. Furuya, S. Mitsunobu, Y. Morita, T. Okada
    KEK, Ibaraki, Japan
 
  SuperKEKB aims for high luminosity on the order of 1035 cm-2s-1 with beam currents of 2.6 A for electron and 3.6 A for positron to search new physics beyond the Standard Model in the B meson regime. In recent operations, we achieved a new record of luminosity of 4.65×1034 cm-2s-1 with 1.1 A for electron and 1.3 A for positron. The SRF system that was designed for KEKB, the predecessor of SuperKEKB, is operating stably with the high beam currents owing to the measures against the large beam powers and the large higher-order-mode (HOM) powers. As a measure against the large beam powers, our SRF cavities have increased a coupling of high-power input couplers during the KEKB operation. As a measure against the large HOM power, newly developed SiC HOM dampers have been installed in the SuperKEKB ring. In addition, we have established the horizontal high-pressure rinse method to recover the cavity performance that has degraded due to vacuum works and accidents in the long-term operation. In this report, we will present our operation experience of SRF system under the high beam currents.  
slides icon Slides MOIXA05 [3.450 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIXA05  
About • Received ※ 19 June 2023 — Revised ※ 21 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 20 July 2023
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WEIXA03 Optimizing the Manufacture of High-Purity Niobium SRF Cavities Using the Forming Limit Diagram: A Case Study of the HL-LHC Crab Cavities RFD Pole cavity, simulation, niobium, SRF 627
 
  • A. Gallifa Terricabras, I. Aviles Santillana, S. Barrière, M. Garlasché, L. Prever-Loiri, J.S. Swieszek
    CERN, Meyrin, Switzerland
  • E. Cano-Pleite
    UC3M, Leganes, Spain
  • M. Narduzzi
    Fermilab, Batavia, Illinois, USA
  • S. Pfeiffer
    European Organization for Nuclear Research (CERN), Geneva, Switzerland
 
  Funding: CERN HL-LHC
The Crab Cavities are key components of the High Luminosity Large Hadron Collider (HL-LHC) project at CERN, which aims to increase the integrated luminosity of the LHC, the world’s largest particle accelerator, by a factor of ten. This paper explores the application of the Forming Limit Diagram (FLD) to enhance the manufacturing process of complex-shape Nb-based cavities, with a focus on the formability challenges experienced with the pole of the Radio Frequency Dipole (RFD) Crab Cavities. The study includes the material characterization of ultra-high-purity niobium (Nb RRR300) sheets, namely mechanical tests and microstructural analysis; it also contains large-deformation Finite Element simulations of the pole deep drawing process, and the translation of the resulting strains in a FLD diagram, together with several suggestions on how to improve the manufacturing process of such deep drawn parts. The results of this study can provide valuable insights into improving the design and fabrication of complex-shaped superconducting radio-frequency cavities made by large-deformation metal-sheet forming processes.
 
slides icon Slides WEIXA03 [15.991 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA03  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 27 June 2023
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THIAA02 RF Performance Results of RF Double Quarter Wave Resonators for LHC High Luminosity Project cavity, HOM, vacuum, radiation 925
 
  • K. Turaj, J. Bastard, R. Calaga, S.J. Calvo, O. Capatina, A. Castilla, M. Chiodini, C. Duval, A.V. Edwards, L.M.A. Ferreira, M. Gourragne, P. Kohler, E. Montesinos, C. Pasquino, G. Pechaud, N. Stapley, N. Valverde Alonso, J.D. Walker
    CERN, Meyrin, Switzerland
  • A. Castilla
    JLAB, Newport News, USA
  • A.V. Edwards
    Lancaster University, Lancaster, United Kingdom
 
  The LHC High Luminosity (HL-LHC) project includes, among other key items, the installation of superconducting crab cavities in the LHC machine. The Double Quarter Wave (DQW) crab cavity will be utilised to compensate for the effects of the vertical crossing angle. Two bare DQW series cavities were manufactured in Germany by RI Research Instruments and validated successfully at CERN through a cold test at 2K. Two DQW series cavities were produced in-house at CERN, integrated into a titanium helium tank, and equipped with RF ancillaries. This paper addresses the cavities preparation processes and summarizes the results of cryogenic tests of DQW cavities at CERN  
slides icon Slides THIAA02 [10.840 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIAA02  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 01 July 2023
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