Author: Albright, S.C.P.
Paper Title Page
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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WEPMP021 Frequency Modulated Capture of Cooled Coasting Ion Beams 2356
 
  • S.C.P. Albright, M.E. Angoletta
    CERN, Geneva, Switzerland
 
  Transverse space charge effects in the Low Energy Ion Ring (LEIR) at CERN have been shown to be a major source of particle losses, which can be mitigated with a larger RMS longitudinal emittance. However, due to electron cooling during the injection plateau, the longitudinal density is very high prior to RF capture. In addition there is an uncontrolled cycle to cycle variation in the revolution frequency of the coasting beam on the flat bottom, which degrades the beam quality at capture. In this paper we show that applying an RF frequency modulation during the capture process allows both a controlled blow-up of the longitudinal emittance and a very good reproducibility in the longitudinal distribution, which in turn improves beam transmission through the machine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP021  
About • paper received ※ 29 April 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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THPRB066 Beam Based Measurements of Relative RF Phase 3950
 
  • S.C.P. Albright
    CERN, Geneva, Switzerland
  • M.D. Kuczynski
    LPCT, Vandoeuvre-lès-Nancy Cedex, France
 
  The ferrite loaded RF cavities of the CERN Proton Synchrotron Booster will be replaced with FinemetTM loaded cavities during Long Shutdown 2 2019-2020). To fully realise the potential of the new cavities, the relative RF phases must be aligned along the acceleration ramp, where the revolution frequency changes by nearly a factor of 2. A beam based method of measuring the relative phase between the cavities is desired to give the best possible compensation for the frequency dependent phase shift. In this paper we present an operationally viable method to measure the phase shift as a function of RF frequency. The relative phase of the RF cavities can be aligned to within a few degrees, giving an error on the voltage seen by the beam of less than 1%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB066  
About • paper received ※ 08 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB067 Time Varying RF Phase Noise for Longitudinal Emittance Blow-Up 3954
 
  • S.C.P. Albright
    CERN, Geneva, Switzerland
  • D. Quartullo
    Sapienza University of Rome, Rome, Italy
 
  RF phase noise was shown to be effective for controlled longitudinal emittance blow-up in the Proton Synchrotron Booster (PSB) at CERN during beam tests in 2017, with further developments in 2018. At CERN, RF phase noise is used operationally in the Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC). In this paper we show that it is suitable for operation with a variety of beam types in the PSB. In the PSB the synchrotron frequency changes by approximately a factor 4 during the 500 ms acceleration ramp, requiring large changes in the frequency band of the noise. During 2018, a new method of calculating the noise parameters has been demonstrated, which gives upper and lower bounds to the noise frequency band that are smoothly varying through the ramp. The new calculation method has been applied to operational beams accelerated in both single and double RF harmonics, the final results are presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB067  
About • paper received ※ 29 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPRB068 Upgrade of CERN’s PSB Digital Low-Level RF System 3958
 
  • M.E. Angoletta, S.C.P. Albright, A. Findlay, M. Jaussi, J.C. Molendijk, N. Pittet
    CERN, Meyrin, Switzerland
 
  The CERN PS Booster (PSB) is the first circular accelerator in the LHC proton injector chain. The upgrade of this four-ring machine is underway within the framework of the LHC Injectors Upgrade project. The existing digital Low-Level RF (LLRF) system will also be upgraded. This paper outlines the LLRF capabilities required, their implementation and the challenges involved. Results of tests carried out to prepare for the LLRF upgrade are given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB068  
About • paper received ※ 13 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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THPRB070 A New Digital Low-Level RF and Longitudinal Diagnostic System for CERN’s AD 3966
 
  • M.E. Angoletta, S.C.P. Albright, A. Findlay, M. Jaussi, J.C. Molendijk, V. R. Myklebust
    CERN, Meyrin, Switzerland
 
  The Antiproton Decelerator (AD) has been routinely providing 3 E7 antiprotons since July 2000 at 100 MeV/c from 3.5 GeV/c. It will be refurbished during the Long Shutdown 2 (LS2) to provide reliable operation for the new Extra Low ENergy Antiproton (ELENA) ring. AD will be equipped with a new digital Low-Level RF (LLRF) system before its restart in 2021. Diagnostics to measure beam intensity, Δp/p and Schottky spectra will also be developed. This paper is an overview of the planned capabilities and implementations, as well as of the challenges to overcome.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB070  
About • paper received ※ 13 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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