Author: Valuch, D.
Paper Title Page
TUPOST007 New Generation of Very Low Noise Beam Position Measurement System for the LHC Transverse Feedback 849
 
  • D. Valuch
    CERN, Meyrin, Switzerland
  • V. Stopjakova
    Slovak University of Technology (STU), Faculty of Electrical Engineering and Information Technology, Bratislava, Slovak Republic
 
  Recent studies showed that the transverse feedback system noise floor in the Large Hadron Collider (LHC) must be reduced by at least factor of two in order to operate the machine with large beam-beam tune shift as foreseen in the High Luminosity (HL) LHC. Also, the future feedback system foreseen to suppress the LHC Crab Cavity noise relies on improved noise performance of the beam position measurement system. An upgrade program was launched to lower the LHC transverse feedback system noise floor during the LHC Long Shutdown II. A new generation, very low noise beam position measurement module was developed and tested with beam. Innovative methods in the RF receiver, digital signal processing, thorough optimization of every element in the signal chain from pickup to the kickers allowed to achieve a significant reduction of the system noise floor. This unprecedented noise performance opens also new possibilities for auxiliary instruments, using the position data from the transverse feedback. The paper presents the new system, notable implementation details and measured performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST007  
About • Received ※ 18 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 30 June 2022
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TUPOST008 Digital Low-Level RF System for the CERN Linac3 Accelerator 853
 
  • D. Valuch, R. Alemany-Fernández, Y. Brischetto, S.J. Faeroe, G. Piccinini, M.E. Soderen
    CERN, Meyrin, Switzerland
 
  A major consolidation of the aging RF system of the CERN Linac3, the ion source for the whole CERN accelerator chain, started during the Long Shutdown II. The main changes were an upgrade of the analogue Low-Level RF system (LLRF) and replacement of the 350 kW tube amplifiers by a solid-state equivalent. The state-of-the-art digital LLRF system enabled new sophisticated features in field manipulations, significantly increased the operational flexibility and improved operational reliability and availability. The paper presents the new architecture, a low noise master clock generator, digital signal processing with direct sampling of the RF signals, pulse parameter measurement or cavity resonance control.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST008  
About • Received ※ 27 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022
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TUPOST037 Reconstruction of Transverse Phase Space From Transverse Feedback Data for Real Time Extraction of Vital LHC Machine Parameters 937
 
  • G. Kotzian, M.E. Soderen, P.S. Solvang, D. Valuch
    CERN, Meyrin, Switzerland
  • V. Stopjakova
    Slovak University of Technology (STU), Faculty of Electrical Engineering and Information Technology, Bratislava, Slovak Republic
 
  The LHC transverse feedback system (ADT) provides bunch by bunch, turn by turn, normalized and digitized beam position signals from four pick-ups per plane and for each beam. Together with already existing powerful computer-based observation systems, this data can be used to reconstruct in real-time the transverse phase space coordinates of the centre-of-charges, for each individual bunch. Such information is extremely valuable for machine operation, or transverse instability diagnostics. This paper aims on discussing and evaluating methods of combining four position signals for such analysis in the presence of noise and with active transverse feedback. Comparisons are made based on the extraction of vital parameters like the fractional tune or transverse activity. Analytical and numerical results are further benchmarked against real beam data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST037  
About • Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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WEIYGD1 Achievements and Performance Prospects of the Upgraded LHC Injectors 1610
 
  • V. Kain, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, F. Antoniou, T. Argyropoulos, F. Asvesta, B. Balhan, M.J. Barnes, D. Barrientos, H. Bartosik, P. Baudrenghien, G. Bellodi, N. Biancacci, A. Boccardi, J.C.C.M. Borburgh, C. Bracco, E. Carlier, D.G. Cotte, J. Coupard, H. Damerau, G.P. Di Giovanni, A. Findlay, M.A. Fraser, A. Funken, B. Goddard, G. Hagmann, K. Hanke, A. Huschauer, M. Jaussi, I. Karpov, T. Koevener, D. Küchler, J.-B. Lallement, A. Lasheen, T.E. Levens, K.S.B. Li, A.M. Lombardi, N. Madysa, E. Mahner, M. Meddahi, L. Mether, B. Mikulec, J.C. Molendijk, E. Montesinos, D. Nisbet, F.-X. Nuiry, G. Papotti, K. Paraschou, F. Pedrosa, T. Prebibaj, S. Prodon, D. Quartullo, E. Renner, F. Roncarolo, G. Rumolo, B. Salvant, M. Schenk, R. Scrivens, E.N. Shaposhnikova, P.K. Skowroński, A. Spierer, F. Tecker, D. Valuch, F.M. Velotti, R. Wegner, C. Zannini
    CERN, Meyrin, Switzerland
 
  To provide HL-LHC performance, the CERN LHC injector chain underwent a major upgrade during an almost 2-year-long shutdown. In the first half of 2021 the injectors were gradually re-started with the aim to reach at least pre-shutdown parameters for LHC as well as for fixed target beams. The strategy of the commissioning across the complex, a summary of the many challenges and finally the achievements will be presented. Several lessons were learned and have been integrated to define the strategy for the performance ramp-up over the coming years. Remaining limitations and prospects for LHC beam parameters at the exit of the LHC injector chain in the years to come will be discussed. Finally, the emerging need for improved operability of the CERN complex will be addressed, with a description of the first efforts to meet the availability and flexibility requirements of the HL-LHC era while at the same time maximizing fixed target physics output.  
slides icon Slides WEIYGD1 [5.905 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYGD1  
About • Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022  
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WEPOPT055 Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022 1983
 
  • N. Biancacci, S.C.P. Albright, R. Alemany-Fernández, D. Alves, M.E. Angoletta, D. Barrientos, H. Bartosik, G. Bellodi, S.B. Bertolo, D. Bodart, M. Bozzolan, H. Damerau, F.D.L. Di Lorenzo, A. Frassier, D. Gamba, A. Huschauer, S. Jensen, V. Kain, T. Koevener, G. Kotzian, D. Küchler, A. Lasheen, G. Le Godec, T.E. Levens, N. Madysa, E. Mahner, O. Marqversen, C.M. Mastrostefano, P.D. Meruga, C. Mutin, M. O’Neil, G. Piccinini, R. Scrivens, P.S. Solvang, D. Valuch, F.M. Velotti, R. Wegner, C. Wetton, M. Zampetakis
    CERN, Meyrin, Switzerland
 
  CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT055  
About • Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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