Author: Gonnella, D.
Paper Title Page
MO2AA02
LCLS-II Commissioning  
 
  • Y. Ding, C. Adolphsen, A. Brachmann, D. Gonnella, F. Zhou
    SLAC, Menlo Park, California, USA
 
  The LCLS-II CW 4 GeV SRF linac will be commissioned during the Spring of 2022. Progress and challenges will be described.  
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THPOJO12 LCLS-II-HE Cryomodule Testing at Fermilab 721
 
  • A.T. Cravatta, T.T. Arkan, D. Bafia, B.E. Chase, M. Checchin, C. Contreras-Martinez, B. Giaccone, B.J. Hansen, E.R. Harms, B.D. Hartsell, J.A. Kaluzny, D.D. Lambert, J.N. Makara, H. Maniar, M. Martinello, Y.M. Pischalnikov, S. Posen, J. Reid, N. Solyak, D. Sun, A. Syed, R. Wang, M.J. White, G. Wu
    Fermilab, Batavia, Illinois, USA
  • S. Aderhold, A.L. Benwell, J.D. Fuerst, D. Gonnella, T. Hiatt, S.L. Hoobler, J.T. Maniscalco, J. Nelson, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • L.R. Doolittle, S. Paiagua, C. Serrano
    LBNL, Berkeley, California, USA
 
  22 Linac Coherent Light Source II (LCLS-II) cryomodules were successfully tested at the Cryomodule Test Facility (CMTF) at Fermilab. Following the completion of the LCLS-II testing program, CMTF has shifted to testing cryomodules for the LCLS-II High Energy upgrade (LCLS-II-HE). The first LCLS-II-HE cryomodule, the verification cryomodule (vCM), was successfully tested and verified the readiness of LCLS-II-HE cryomodule testing at CMTF, and production cryomodule testing has begun. Presented here are the production cryomodule test acceptance criteria, testing plan, and cryomodule test results so far.  
poster icon Poster THPOJO12 [0.899 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO12  
About • Received ※ 18 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 06 September 2022 — Issue date ※ 15 September 2022
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THPOPA15 Anomaly Detection Based Quench Detection System for CW Operation of SRF Cavities 775
 
  • G. Martino, A. Bellandi, J. Branlard, A. Eichler, H. Schlarb
    DESY, Hamburg, Germany
  • S. Aderhold, A.L. Benwell, D. Gonnella, S.L. Hoobler, J. Nelson, R.D. Porter, A. Ratti, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • L.R. Doolittle
    LBNL, Berkeley, California, USA
  • G. Fey
    Hamburg University of Technology, Hamburg, Germany
 
  Funding: This work is supported by DASHH (Data Science in Hamburg - HELMHOLTZ Graduate School for the Structure of Matter) under Grant No.: HIDSS-0002.
Superconducting radio frequency (SRF) cavities are used in modern particle accelerators to take advantage of their very high quality factor (Q). A higher Q means that a higher RF field can be sustained, and a higher acceleration can be produced in the cavity for length unity. However, in certain situations, e.g., too high RF field, the SRF cavities can experience quenches that risk creating damage due to the rapid increase in the heat load. This is especially negative in continuous wave (CW) operation due to the impossibility of the system to recover during the off-load period. The design goal of a quench-detection system is to protect the system without being a limiting factor during the operation. In this paper, we compare two different classification approaches for improving a quench detection system. We perform tests using traces recorded from LCLS-II and show that the ARSENAL classifier outperforms a CNN classifier in terms of accuracy.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA15  
About • Received ※ 24 August 2022 — Accepted ※ 25 August 2022 — Issue date ※ 23 September 2022  
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THPOPA21 Narrow Bandwidth Active Noise Control for Microphonics Rejection in Superconducting Cavities at LCLS-II 785
SUPCPA06   use link to see paper's listing under its alternate paper code  
 
  • A. Bellandi, J. Branlard
    DESY, Hamburg, Germany
  • S. Aderhold, A.L. Benwell, A. Brachmann, J.A. Diaz Cruz, D. Gonnella, S.L. Hoobler, J. Nelson, A. Ratti, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • R.D. Porter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  LCLS-II is an X-Ray Free Electron Laser (XFEL) under commissioning at SLAC, being the first Continuous Wave (CW) hard XFEL in the world to come into operation. To accelerate the electron beam to an energy of 4 GeV, 280 superconducting cavities of the TESLA types are used. A Loaded Q (QL) value of 4x107 is used to drive the cavities at a power level of a few kilowatts. For this QL value, the RF cavity bandwidth is equal to 32 Hz. Therefore, keeping the cavity resonance frequency within such bandwidth is imperative to avoid a significant increase in the required RF power. In superconducting accelerators, resonance frequency variations are produced by mechanical microphonic vibrations of the cavities. One source of microphonics noise is rotary machinery such as vacuum pumps or HVAC equipment. A possible method to reject these disturbances is to use Narrowband Active Noise Control (NANC) techniques. Such a technique was already tested at DESY/CMTB and Cornell/CBETA. This proceeding presents the implementation of a NANC controller in the LCLS-II Low Level RF (LLRF) control system. Tests on the rejection of LCLS-II microphonics disturbances are also presented.  
poster icon Poster THPOPA21 [1.843 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA21  
About • Received ※ 24 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 26 September 2022
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