Author: Antoniou, F.
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MOPGW094 First Machine Developments Result with HL-LHC Crab Cavities in the SPS 338
 
  • L.R. Carver, A. Alekou, F. Antoniou, H. Bartosik, T. Bohl, R. Calaga, M. Carlà, T.E. Levens, G. Papotti
    CERN, Geneva, Switzerland
  • A. Alekou, R.B. Appleby, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • G. Burt
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, J.A. Mitchell
    Lancaster University, Lancaster, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
 
  Crab cavities are a critical component within the High Luminosity upgrade project for the Large Hadron Collider (HL-LHC). It is foreseen to use crab cavities in order to compensate the geometric luminosity reduction factor (reduction of the luminous region at the Interaction Point [IP]) due to the beam crossing angle (required for minimizing the impact of the long range beam-beam effects on the single particle beam dynamics) and increase the number of collisions per bunch crossing. In 2018 the first beam tests of crab cavities with protons were performed in the Super Proton Synchrotron (SPS) at CERN. Two vertical superconducting cavities of the Double Quarter Wave (DQW) type were fabricated and installed in the SPS to verify some key components of the cavity design and operation. This paper will present some of the first results relating to the proton beam dynamics in the presence of crab cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW094  
About • paper received ※ 25 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS085 Commissioning of a New Digital Transverse Damper System at the PSB 1050
 
  • G.P. Di Giovanni, F. Antoniou, A. Blas, Y. Brischetto, A. Findlay, G. Kotzian, B. Mikulec, G. Sterbini
    CERN, Geneva, Switzerland
 
  At the CERN Proton Synchrotron Booster, PSB, an analog transverse damper system has been in operation since 1999, providing satisfactory operational results with the proton beam supplied by Linac2. As a consequence of the LHC Injectors Upgrade, the PSB will face new challenges imposed by higher intensity, injection and extraction energy. In this framework, the transverse feedback system is subject to an upgrade to adapt to the expected Linac4 beam and to the demands for new features including transverse blow-up, beam excitation for optics measurements and new remote control and monitoring capabilities. The replacement of the aging electronic hardware is also recommended to improve the system maintainability for future years. During 2018 a new digital transverse feedback electronics was installed in the PSB, in parallel with the current operational one, offering for the first time the occasion to demonstrate its performance with beam. Encouraging results were obtained such as the suppression of beam instabilities at all PSB energies and intensities. In this paper we describe the steps undertaken in 2018 in order to commission the system with the main goal to accelerate and extract the highest intensity beams produced at the PSB.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS085  
About • paper received ※ 06 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPTS086 Identification and Compensation of Betatronic Resonances in the Proton Synchrotron Booster at 160 Mev 1054
 
  • A. Santamaría García, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, G.P. Di Giovanni, B. Mikulec
    CERN, Geneva, Switzerland
  • F. Asvesta
    NTUA, Athens, Greece
  • H. Rafique
    University of Manchester, Manchester, United Kingdom
 
  The Proton Synchrotron Booster (PSB) is the first circular accelerator in the injector chain to the Large Hadron Collider (LHC) and accelerates protons from 50 MeV to 1.4 GeV. The PSB will need to deliver two times the current brightness after the LHC Injectors Upgrade (LIU) in order to meet the High Luminosity LHC (HL-LHC) beam requirements. At the current injection energy a large incoherent space charge tune spread limits the brightness of the beams, which is one of the main motivations to increase the injection energy to 160 MeV with the injection provided by Linac4, a new H linear accelerator. The higher injection energy will allow doubling the beam intensity while maintaining a space charge tune spread similar to current values. The degradation of the beam brightness due to the tune spread can be minimized with a proper choice of working point and an efficient compensation of resonances. In this paper, we present the measurement of the betatronic resonances in the four rings of the PSB at 160 MeV before the Long Shutdown 2, as well as the results of a proposed compensation scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS086  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS087 Transverse Emittance Studies at Extraction of the CERN PS Booster 1058
 
  • F. Antoniou, S.C.P. Albright, F. Asvesta, H. Bartosik, G.P. Di Giovanni, V. Forte, M.A. Fraser, A. Garcia-Tabares, A. Huschauer, B. Mikulec, T. Prebibaj, A. Santamaría García, P.K. Skowroński
    CERN, Meyrin, Switzerland
  • F. Asvesta
    NTUA, Athens, Greece
  • T. Prebibaj
    National Technical University of Athens, Zografou, Greece
 
  Transverse emittance discrepancy in the beam transfer between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is observed in operational conditions for the LHC beams at CERN. The ongoing LHC Injectors Upgrade (LIU) project requires a tight budget for beam degradation along the injector chain and therefore the reason for this emittance discrepancy needs to be understood. Systematic measurements have been performed for various beam characteristics (beam intensity, transverse and longitudinal emittance). In this paper, a comparison between the emittance measurements using all available beam instrumentation with different emittance computation algorithms is presented. The results are compared to measurements at PS injection. Furthermore, the impact on the LIU project requirements for the emittance preservation along the LHC Injectors Complex is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS087  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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MOPTS097 Updates on Alternative Pre-Booster Ring Design and Wiggler Magnet Considerations of SPS for the FCC e+e Injector 1094
 
  • O. Etisken
    Ankara University, Faculty of Sciences, Ankara, Turkey
  • F. Antoniou, Y. Papaphilippou, T. Tydecks
    CERN, Geneva, Switzerland
  • A.K. Çiftçi
    Izmir University of Economics, Balçova/Izmir, Turkey
 
  The Future Circular e+e Collider (FCC- e+e) injector complex needs to produce and to transport a high-intensity e+e beam at a fast repetition rate for topping up the collider at its collision energy. Two different options are under consideration as pre-accelerator before the bunches are transferred to the high-energy booster: using the existing SPS and designing a completely new ring. The purpose of this paper is to explore the needs and parameters of the existing SPS, to investigate wiggler magnet options for SPS, and provide an updated study of alternative accelerator ring design with injection and extraction energies of 6 and 20 GeV, respectively. In this study, the parameters of both choices are established, including the optics design, layout update and considerations for non-linear dynamics optimization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS097  
About • paper received ※ 06 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS101 Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation 1110
 
  • A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis
    CERN, Geneva, Switzerland
  • E. Senes
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
 
  Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP026 Emittance Dilution from the CERN Proton Synchrotron Booster’s Extraction Kickers 2371
 
  • M.A. Fraser, S.C.P. Albright, F. Antoniou, G.P. Di Giovanni, Y. Dutheil, V. Forte, A. Huschauer, F. Roncarolo
    CERN, Meyrin, Switzerland
 
  Understanding the different sources of emittance dilution along the LHC injector chain is an important part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantify the transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS). In this contribution, the waveform measurement technique will be briefly outlined before the results and their implications for the LIU project and beam performance reach are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP026  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPTS041 Coupling and Space Charge Studies at the CERN PSB 3192
 
  • F. Asvesta
    NTUA, Athens, Greece
  • F. Antoniou, H. Bartosik, G.P. Di Giovanni, Y. Papaphilippou
    CERN, Meyrin, Switzerland
 
  In the nominal optics of the CERN PS-Booster (PSB), the fourth order coupling resonance is excited by space charge (Montague resonance) due to the same integer tune values. This resonance can be avoided by changing the tunes to different integers. A new PSB optics is presented and emittance measurements crossing the coupling resonance for the nominal and the new optics are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS041  
About • paper received ※ 17 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS046 Monitoring and Modelling of the LHC Emittance and Luminosity Evolution in 2018 3212
 
  • S. Papadopoulou, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, N. Karastathis, S. Kostoglou, Y. Papaphilippou, G. Trad
    CERN, Meyrin, Switzerland
 
  Operating at 6.5 TeV, the LHC surpassed the expectations and delivered an average of 66 fb−1 integrated luminosity to the two high luminosity experiments ATLAS and CMS by the end of 2018. In order to provide a continuous feedback to the machine coordination for further optimizing the performance, an automated tool for monitoring the main beam parameters and machine configurations, has been devised and extensively used. New features like the coupling between the two planes and effects of noise, were added to the numerical model used since 2016 to calculate the machine luminosity. Estimates, based both on simulations and on observed beam parameters, were reported fill-by-fill as well as in overall trends during the year. Highlights of the observations including the observed additional emittance blow up (on top of IBS, SR and elastic scattering) as well as additional losses (on top of the expected proton burn off) are presented for the 2018 data. Finally, cumulated integrated luminosity projections from the model for the entire 2018 data based on different degradation mechanisms are compared also with respect to the achieved luminosity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS046  
About • paper received ※ 17 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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