Author: Lari, L.
Paper Title Page
MOPRO037 Collimator Fast Failure Losses for Various HL-LHC Configurations 157
 
  • L. Lari, R. Bruce, S. Redaelli
    CERN, Geneva, Switzerland
  • L. Lari
    IFIC, Valencia, Spain
 
  Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The upgrade of the Large Hadron Collider (LHC), in terms of beam intensity and energy, implies an increasing risk of severe damage in particular in case of fast failures losses. For this reason, efforts were put in developing simulation tools to allow studies of asynchronous dump accident, including realistic failure cases for collimator settings and machine parameters like orbit and optics. The scope of these studies is to understand realistic beam loads in different collimators, in order to improve the actual LHC collimator system design, to provide feedbacks on optic design and to evaluate different mitigation actions. Simulations were set up with a modified SixTrack collimation routine able to simulate erroneous firing of a single dump kicker or the simultaneous malfunction of all the 15 kickers. In such a context, results are evaluated from the whole LHC collimation system point of view.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO037  
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MOPRO043 Handling 1 MW Losses with the LHC Collimation System 174
 
  • B. Salvachua, R. Bruce, F. Carra, M. Cauchi, E.B. Holzer, W. Höfle, D. Jacquet, L. Lari, D. Mirarchi, E. Nebot Del Busto, S. Redaelli, A. Rossi, M. Sapinski, R. Schmidt, G. Valentino, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  • M. Cauchi
    UoM, Msida, Malta
  • L. Lari
    IFIC, Valencia, Spain
 
  Funding: Research supported by EU FP7 HiLumi LHC (Grant agree. 284404)
The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking from the betatron collimation system and represent the main limitation for the halo cleaning. In 2013, quench tests were performed at 4 TeV to improve the quench limit estimates, which determine the maximum allowed beam loss rate for a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the magnets did not quench.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO043  
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THPRI011 Beam-machine Interaction at TLEP: First Evaluation and Mitigation of the Synchrotron Radiation Impact 3785
 
  • L. Lari, F. Cerutti, A. Ferrari, A. Mereghetti
    CERN, Geneva, Switzerland
  • L. Lari
    IFIC, Valencia, Spain
  • A. Mereghetti
    UMAN, Manchester, United Kingdom
 
  In the framework of post-LHC accelerator studies, TLEP is a proposed high-luminosity circular e+e collider, aimed at measuring the properties of the Higgs-boson H(126) with unprecedented accuracy, as well as those of the W boson, the Z boson and the top quark. In order to calculate the impact of synchrotron radiation, the latter has been implemented in the FLUKA code as new source term. A first account of escaping power as a function of the vacuum chamber shielding thickness, photoneutron production, and activation has been obtained for the 80km circumference 175 GeV (beam energy) TLEP option. Starting from a preliminary layout of the FODO cell and a possible dipole design, energy deposition simulations have been carried out, investigating the effectiveness of absorbers in the interconnections. The results provide inputs to improve the cell design and to support mechanical integration studies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI011  
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MOPRO035 Update on Nonlinear Collimation Schemes for the LHC 151
 
  • J. Resta-López
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Faus-Golfe, L. Lari, J. Resta-López
    IFIC, Valencia, Spain
 
  Funding: FP7 HL-LHC Grant Agreement 284404
In this paper we review the status of the studies on nonlinear collimation schemes for the LHC. Concretely we describe the design of a nonlinear optics for betatron cleaning in IR7. The aim is to investigate alternative nonlinear collimation systems to reduce the collimator-induced impedance that may limit the beam intensity towards the LHC luminosity upgrade. The performance of the LHC nonlinear collimation system is studied by means of tracking simulations and compared with the present LHC system. Furthermore, the advantages and possible limitations of such nonlinear collimation scheme are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO035  
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MOPRO039 Integrated Simulation Tools for Collimation Cleaning in HL-LHC 160
 
  • R. Bruce, C. Bracco, F. Cerutti, A. Ferrari, A. Lechner, A. Marsili, A. Mereghetti, D. Mirarchi, P.G. Ortega, D. Pastor Sinuela, S. Redaelli, A. Rossi, B. Salvachua, V. Vlachoudis
    CERN, Geneva, Switzerland
  • R. Appleby, J. Molson, M. Serluca
    UMAN, Manchester, United Kingdom
  • R.W. Aßmann
    DESY, Hamburg, Germany
  • R.J. Barlow, H. Rafique, A.M. Toader
    University of Huddersfield, Huddersfield, United Kingdom
  • S.M. Gibson, L.J. Nevay
    Royal Holloway, University of London, Surrey, United Kingdom
  • L. Lari
    IFIC, Valencia, Spain
  • C. Tambasco
    University of Rome La Sapienza, Rome, Italy
 
  The Large Hadron Collider is designed to accommodate an unprecedented stored beam energy of 362~MJ in the nominal configuration and about the double in the high-luminosity upgrade HL-LHC that is presently under study. This requires an efficient collimation system to protect the superconducting magnets from quenches. During the design, it is therefore very important to accurately predict the expected beam loss distributions and cleaning efficiency. For this purpose, there are several ongoing efforts in improving the existing simulation tools or developing new ones. This paper gives a brief overview and status of the different available codes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO039  
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