Author: Uythoven, J.A.
Paper Title Page
MOOCB01 Beam-induced Quench Tests of LHC Magnets 52
 
  • M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto
    CERN, Geneva, Switzerland
 
  At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 108 to 1013. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.  
slides icon Slides MOOCB01 [2.737 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01  
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MOPRO020 FLUKA Simulation of Particle Fluences to ALICE due to LHC Injection Kicker Failures 109
 
  • N.V. Shetty, C. Bracco, A. Di Mauro, A. Lechner, E. Leogrande, J.A. Uythoven
    CERN, Geneva, Switzerland
 
  The counter-rotating beams of the LHC are injected in insertion regions which also accommodate the ALICE and LHCb experiments. An assembly of beam absorbers ensures the protection of machine elements in case of injection kicker failures, which can affect either the injected or the stored beam. In the first years of LHC operation, secondary particle showers due to beam impact on the injection beam stopper caused damage to the MOS injectors of the ALICE silicon drift detector as well as high-voltage trips in other ALICE subdetectors. In this study, we present FLUKA simulations of particle fluences to the ALICE cavern for injection failures encountered during operation. Two different cases are reported, one where the miskicked beam is fully intercepted and one where the beam grazes the beam stopper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO020  
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MOPRO029 Feed Forward Orbit Correction in the CLIC Ring to Main LINAC Transfer Lines 131
 
  • R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven
    CERN, Geneva, Switzerland
 
  The emittance growth in the betatron collimation system of the 27 km long transfer lines between the CLIC damping rings and the main LINAC depends strongly on the transverse orbit jitter. The resulting stability requirements of the damping ring extraction elements seem extremely difficult to achieve. Position and angle feed forward systems in these long transfer lines bring the specified parameters of the extraction elements within reach. The designs of the optics and feed forward hardware are presented together with tracking simulations of the systems.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO029  
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MOPRO030 Changes to the LHC Beam Dumping System for LHC Run 2 134
 
  • J.A. Uythoven, M.G. Atanasov, J. Borburgh, E. Carlier, S. Gabourin, B. Goddard, N. Magnin, V. Senaj, N. Voumard, W.J.M. Weterings
    CERN, Geneva, Switzerland
 
  The LHC beam dumping system performed according to expectations during Run 1 of the LHC (2009 – 2013). A brief overview of the experience is given, including a summary of the observed performance in comparison to expectations. An important number of changes are applied to the beam dumping system during the present Long Shutdown on order to further improve its system safety and performance. They include the addition of a direct link between the Beam Interlock System and the re-triggering system of the dump kickers, the modification of the uninterrupted electrical power distribution architecture, the upgrade of the HV generators, the consolidation of the trigger synchronization system, the modifications to the triggering system of the power switches and the changes to the dump absorbers TCDQ.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO030  
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MOPRO031 Abort Gap Cleaning for LHC Run 2 138
 
  • J.A. Uythoven, A. Boccardi, E. Bravin, B. Goddard, G.H. Hemelsoet, W. Höfle, D. Jacquet, V. Kain, S. Mazzoni, M. Meddahi, D. Valuch
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois, USA
 
  To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO031  
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MOPRO032 Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project 141
 
  • J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele
    CERN, Geneva, Switzerland
 
  The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032  
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MOPME049 Design Considerations of the Final Turnaround Regions for the CLIC Drive Beam 485
 
  • R. Apsimon, J. Esberg, A. Latina, D. Schulte, J.A. Uythoven
    CERN, Geneva, Switzerland
 
  The optics design of the final turnaround regions for the CLIC drive beam is presented. This includes the extraction region, the turnaround loop and the phase feed forward chicane for correcting errors on the bunch phase. The design specifications of the kicker and septum magnets are provided. Tracking simulations and detailed studies of coherent and incoherent synchrotron radiation have been used to optimise the optics in the turnaround region in order to minimise transverse and longitudinal emittance growth.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME049  
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MOPME076 Upgrade of the SPS Injection Kicker System for LHC High Luminosity Operation with Heavy Ion Beam 547
 
  • T. Kramer, J. Borburgh, L. Ducimetière, B. Goddard, L. Sermeus, J.A. Uythoven, F.M. Velotti
    CERN, Geneva, Switzerland
 
  In the context of the LHC High Luminosity Upgrade project a performance upgrade for heavy ions is envisaged. One of the performance limitations is the rise time of the present SPS injection kicker system MKP. A reduction of the rise time for lead ions was studied in line with a modification of the whole injection system. This paper briefly describes the different rise time options studied for an initially proposed dedicated ion kicker system MKP-I, focuses however on a cost effective alternative using the presently installed 12 MKPS magnets connected to a new fast pulse forming line. As only 12 out of the 16 injection kicker magnets would be fast enough to be used in an upgraded system, additional deflection has to be provided by the septa. The beam optics for that variant is highlighted and first requirements for the septum elements are stipulated. The paper concludes with a failure analysis of the proposed scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME076  
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TUPRI030 Beam Coupling Impedance of the New Beam Screen of the LHC Injection Kicker Magnets 1627
 
  • H.A. Day, M.J. Barnes, F. Caspers, E. Métral, B. Salvant, J.A. Uythoven
    CERN, Geneva, Switzerland
 
  The LHC injection kicker magnets experienced significant beam induced heating of the ferrite yoke, with high intensity beam circulating for many hours, during operation of the LHC in 2011 and 2012. The causes of this beam coupling impedance were studied in depth and an improved beam screen implemented to reduce the impedance. Results of measurements and simulations of the new beam screen design are presented in this paper: these are used to predict power loss and temperature of the ferrite yoke for operation after long shutdown 1 and for proposed HL-LHC operational parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI030  
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THPRI021 Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-triggering Lines 3810
 
  • S. Gabourin, E. Carlier, R. Denz, N. Magnin, J.A. Uythoven, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  • M. Bartholdt, B. Bertsche, V. Vatansever, P. Zeiler
    Universität Stuttgart, Stuttgart, Germany
 
  To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a reliability analysis to quantify its impact on LHC machine availability are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI021  
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