Author: Borburgh, J.C.C.M.
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MOPIK042 Beam-Based Kicker Waveform Measurements Using Long Bunches 599
 
  • V. Forte, W. Bartmann, J.C.C.M. Borburgh, M.A. Fraser, L. Sermeus
    CERN, Geneva, Switzerland
 
  The increased bunch length demanded by the LHC Injectors Upgrade (LIU) project to mitigate emittance growth from space-charge on the PS injection plateau puts strong constraints on the rise-times of the recombination kickers in the transfer lines between the CERN Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS). A beam-based technique has been developed to validate the waveforms of the recombination kickers. In this paper high-resolution measurements are presented by extracting the intra-bunch deflection along bunches with lengths comparable to or longer than the rise-time of the kicker being probed. The methodology has been successfully applied to the three vertical recombination kickers named BT1. KFA10, BT4. KFA10 and BT2. KFA20, and benchmarked with direct measurements of the kicker field made using a magnetic field probe. This paper describes the beam-based technique, summarises the main characteristics of the measured waveforms, such as rise-time and flat-top ripple, and estimates their impact on beam brightness.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK042  
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MOPIK043 Beam-Based Waveform Measurements of the CERN PS Injection Kicker 603
 
  • V. Forte, W. Bartmann, J.C.C.M. Borburgh, L.M.C. Feliciano, A. Ferrero Colomo, M.A. Fraser, T. Kramer, L. Sermeus
    CERN, Geneva, Switzerland
 
  In the framework of the LHC Injectors Upgrade (LIU) project, a beam-based technique has been developed for measuring the waveform the CERN Proton Synchrotron (PS) horizontal injection kicker, named KFA45. The technique avoids the need for tedious magnetic measurements, especially when a spare magnet is presently unavailable and measuring the operational magnet with a magnetic field probe is complicated by integration reasons. In this paper, the technique and results of the waveform measurements are summarised. The results already provide additional information in terms of waveform characterisation for the validation of numerical simulations and are of great interest for the future LIU performance upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK043  
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MOPIK044 The Use of a Passive Scatterer for SPS Slow Extraction Beam Loss Reduction 607
 
  • B. Goddard, B. Balhan, J.C.C.M. Borburgh, M.A. Fraser, L.S. Stoel, F.M. Velotti
    CERN, Geneva, Switzerland
 
  A significant reduction in the fraction of protons lost on the SPS electrostatic septum ES during resonant slow extraction is highly desirable for present Fixed-Target beam operation, and will become mandatory for the proposed SHiP experiment, which is now being studied in the framework of CERN's Physics Beyond Colliders program. In this paper the possible use of a passive scattering device (diffuser) is investigated. The physics processes underlying the use of a diffuser are described, and the dependence on the diffuser geometry, material and location of the potential loss reduction on the electrostatic septum (ES) wires is investigated with a semi-analytical approach. Numerical simulations to quantify the expected performance gain for the optimum configuration are presented, and the results discussed in view of the feasibility of a potential realisation in the SPS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK044  
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MOPIK045 SPS Slow Extraction Losses and Activation: Challenges and Possibilities for Improvement 611
 
  • M.A. Fraser, B. Balhan, H. Bartosik, C. Bertone, D. Björkman, J.C.C.M. Borburgh, N. Conan, K. Cornelis, R. Garcia Alia, L. Gatignon, B. Goddard, Y. Kadi, V. Kain, A. Mereghetti, F. Roncarolo, P.M. Schicho, J. Spanggaard, O. Stein, L.S. Stoel, F.M. Velotti, H. Vincke
    CERN, Geneva, Switzerland
 
  In 2015 the highest integrated number of protons in the history of the North Area was slow extracted from the CERN Super Proton Synchrotron (SPS) for the Fixed Target physics programme. At well over 1.1019 protons on target (POT), this represented the highest annual figure at SPS for almost two decades, since the West Area Neutrino Facility was operational some 20 years ago. The high intensity POT requests have continued into 2016-17 and look set to do so for the foreseeable future, especially in view of the proposed SPS Beam Dump Facility and experiments, e.g. SHiP*, which are requesting up to 4·1019 POT per year. Without significant improvements, the attainable annual POT will be limited to well below the total the SPS machine could deliver, due to activation of accelerator equipment and associated personnel dose limitations. In this contribution, the issues arising from the recent high activation levels are discussed along with the steps taken to understand, manage and mitigate these issues. The research avenues being actively pursued to improve the slow extraction related beam loss for present operation and future requests are outlined, and their relative merits discussed.
*A. Golutvin et al., ‘‘A Facility to Search for Hidden Particles (SHiP) at the CERN SPS'', CERN, Geneva, Switzerland, Rep. CERN-SPSC-2015-016 (SPSC-P-350), Apr. 2015.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK045  
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WEPVA023 Performance of the PS Injection Kicker System Short Circuit Mode Upgrade for Operation with 2 GeV LIU Beams 3308
 
  • T. Kramer, W. Bartmann, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, A. Ferrero Colomo, B. Goddard, L. Sermeus
    CERN, Geneva, Switzerland
 
  In the framework of the LHC Injector Upgrade (LIU) project an upgrade of the existing PS proton injection kicker system for 2 GeV operation is in progress. The upgrade is based on the operation of the existing kicker system in short circuit mode. This paper briefly reviews the deployed modifications to the system to obtain the specified reduction of pulse reflections unavoidably induced by such a configuration. The implementation of improvements to the magnet entry box, transmission cables and the short circuit plug with integrated LC-filter are described as well as tests and measurements during the 2016/17 annual shutdown. The impact of the residual pulse shape structure on the beam performance for the reference LIU beam is quantified. The paper concludes with a performance analysis, a comparison of measurements vs. simulations and an outlook to the remaining modifications during the next long shut down.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA023  
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