Author: Mereghetti, A.
Paper Title Page
MOPAB003 Energy Deposition in the Betatron Collimation Insertion of the 100 TeV Future Circular Collider 68
 
  • M.I. Besana, C. Bahamonde Castro, A. Bertarelli, R. Bruce, F. Carra, F. Cerutti, A. Ferrari, M. Fiascaris, A. Lechner, A. Mereghetti, S. Redaelli, E. Skordis, V. Vlachoudis
    CERN, Geneva, Switzerland
 
  The FCC proton beam is designed to carry a total energy of about 8500 MJ, a factor of 20 above the LHC. In this context, the collimation system has to deal with extremely tight requirements to prevent quenches and material damage. A first layout of the betatron cleaning insertion was conceived, adapting the present LHC collimation system to the FCC lattice. A crucial ingredient to assess its performance, in particular to estimate the robustness of the protection devices and the load on the downstream elements, is represented by the simulation of the particle shower generated at the collimators, allowing detailed energy deposition estimations. This paper presents the first results of the simulation chain starting from the proton losses generated with the Sixtrack-FLUKA coupling, as currently done for the present LHC and for its upgrade. Expectations in terms of total power, peak power density and integrated dose on the different accelerator components are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB003  
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MOPAB004 Improved Protection of the Warm Magnets of the LHC Betatron Cleaning Insertion 72
 
  • C. Bahamonde Castro, F. Cerutti, P. Fessia, A. Lechner, A. Mereghetti, D. Mirarchi, S. Redaelli, E. Skordis
    CERN, Geneva, Switzerland
  • E. Skordis
    The University of Liverpool, Liverpool, United Kingdom
 
  After the High Luminosity (HL) upgrade in 2024-2026, the LHC is anticipated to increase its integrated luminosity by a factor of 10 beyond its original design value of 300 fb-1. In preparation for this, several improvements to the equipment will already be implemented during the next Long Shutdown (LS2) starting in 2019. In the betatron cleaning insertion, the debris leaking out of several collimators will deposit energy in the downstream warm magnets, causing long-term radiation damage. A new layout has been proposed in which the most exposed magnet of each assembly is removed, reducing the assembly from 6 to 5 magnet units and gaining 2 spare magnets. New absorbers are therefore required to enhance the shielding of the remaining magnet string. In this paper, we present an evaluation of the dose to the warm magnets for post-LS2 operation, and we quantify the achievable reduction of the long-term radiation damage for different absorber configurations. A solution for an improved magnet protection that fulfills the HL-LHC requirements is proposed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB004  
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MOPAB012 Study of the 2015 Top Energy LHC Collimation Quench Tests Through an Advanced Simulation Chain 100
SUSPSIK009   use link to see paper's listing under its alternate paper code  
 
  • E. Skordis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • R. Bruce, F. Cerutti, A. Ferrari, P.D. Hermes, A. Lechner, A. Mereghetti, S. Redaelli, B. Salvachua, E. Skordis, V. Vlachoudis
    CERN, Geneva, Switzerland
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  While the LHC has shown record-breaking perfor-mance during the 2016 run, our understanding of the behaviour of the machine must also reach new levels. The collimation system and especially the betatron cleaning insertion region (IR7), where most of the beam halo is intercepted to protect superconducting (SC) magnets from quenching, has so far met the expectations but could nonetheless pose a bottleneck for future operation at higher beam intensities for HL-LHC. A better under-standing of the collimation leakage to SC magnets is required in order to quantify potential limitations in terms of cleaning efficiency, ultimately optimising the collider capabilities. Particle tracking simulations com-bined with shower simulations represent a powerful tool for quantifying the power deposition in magnets next to the cleaning insertion. In this study, we benchmark the simulation models against beam loss monitor measure-ments from magnet quench tests (QT) with 6.5 TeV pro-ton and 6.37Z TeV Pb ion beams. In addition, we investi-gate the effect of possible imperfections on the collima-tion leakage and the power deposition in magnets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB012  
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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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TUPVA014 The 2016 Proton-Nucleus Run of the LHC 2071
 
  • J.M. Jowett, R. Alemany-Fernández, G. Baud, P. Baudrenghien, R. De Maria, R. De Maria, D. Jacquet, M.A. Jebramcik, A. Mereghetti, T. Mertens, M. Schaumann, H. Timko, M. Wendt, J. Wenninger
    CERN, Geneva, Switzerland
 
  For five of the LHC experiments the second p-Pb collision run planned in 2016 offered the opportunity to answer a range of important physics questions arising from the surprise discoveries (e.g., flow-like collective phenomena in small systems) made in earlier Pb-Pb, p-Pb and p-p runs. However the diversity of the physics and their respective capabilities led them to request very different operating conditions, in terms of collision energy, luminosity and pile-up. These appeared mutually incompatible within the available one month of operation. Nevertheless, a plan to satisfy most requirements was developed and implemented successfully. It exploited different beam lifetimes at two beam energies of 4 Z TeV and 6.5 Z TeV, a variety of luminosity sharing and bunch filling schemes, and varying beam directions. The outcome of this very complex strategy for repeated re-commissioning and operation of the LHC included the longest ever LHC fill with luminosity levelled for almost 38 h. The peak luminosity achieved exceeded the design value by a factor 7.8 and integrated luminosity substantially exceeded the experiments' requests.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA014  
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WEOBA1 A Comparison of Interaction Physics for Proton Collimation Systems in Current Simulation Tools 2478
 
  • J. Molson, A. Faus-Golfe
    LAL, Orsay, France
  • R.B. Appleby, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • R.J. Barlow
    IIAA, Huddersfield, United Kingdom
  • R. Bruce, F. Cerutti, A. Ferrari, A. Mereghetti, S. Redaelli, K.N. Sjobak, V. Vlachoudis
    CERN, Geneva, Switzerland
  • H. Rafique
    University of Manchester, Manchester, United Kingdom
  • Y. Zou
    IHEP, Beijing, People's Republic of China
 
  Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305.
High performance collimation systems are required for current and proposed high energy hadron accelerators in order to protect superconducting magnets and experiments. In order to ensure that the collimation system designs are sufficient and will operate as expected, precision simulation tools are required. This paper discusses the current status of existing collimation system tools, and performs a comparison between codes in order to ensure that the simulated interaction physics between a proton and a collimator jaw is accurate.
 
slides icon Slides WEOBA1 [7.235 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA1  
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WEPIK030 Experimental Validation of the Achromatic Telescopic Squeezing Scheme at the LHC 2992
 
  • S.D. Fartoukh, R. Bruce, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, E.H. Maclean, L. Malina, A. Mereghetti, D. Mirarchi, T. Persson, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, P.K. Skowroński, M. Solfaroli, R. Tomás, D. Valuch, A. Wegscheider, J. Wenninger
    CERN, Geneva, Switzerland
 
  The Achromatic Telescopic Squeezing (ATS) [1] scheme offers new techniques to deliver unprecedentedly small beam spot size at the interaction points of the ATLAS and CMS experiments of the LHC, while perfectly controlling the chromatic properties of the corresponding optics (linear and non-linear chromaticities, off-momentum beta-beating, spurious dispersion induced by the crossing bumps). The first series of beam tests with ATS optics were achieved during the LHC Run I (2011/2012) for a first validation of the basics of the scheme at small intensity. In 2016, a new generation of more performing ATS optics was developed and more extensively tested in the machine, still with probe beams for optics measurement and correction at β*=10 cm, but also with a few nominal bunches to establish first collisions at nominal β* (40 cm) and beyond (33 cm), and to analysis the robustness of these optics in terms of collimation and machine protection. The paper will highlight the most relevant and conclusive results which were obtained during this second series of ATS tests.
[1] S. Fartoukh , Phys. Rev. ST Accel. Beams 16, 111002
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK030  
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THPAB046 SixTrack for Cleaning Studies: 2017 Updates 3811
 
  • A. Mereghetti, R. Bruce, F. Cerutti, R. De Maria, A. Ferrari, M. Fiascaris, P.D. Hermes, D. Mirarchi, P.G. Ortega, D. Pastor Sinuela, E. Quaranta, S. Redaelli, K.N. Sjobak, V. Vlachoudis
    CERN, Geneva, Switzerland
  • J. Molson
    LAL, Orsay, France
  • Y. Zou
    IHEP, Beijing, People's Republic of China
 
  SixTrack is a single particle tracking code for simulating beam dynamics in ultra-relativistic accelerators. It is widely used at the European Organisation for Nuclear Research (CERN) for predicting dynamic aperture and cleaning inefficiency in large circular machines like the Super Proton Synchrotron (SPS), the Large Hadron Collider (LHC) and the Future Circular Collider (FCC). The code is under continuous development, to both extend its physics models, and enhance performance. The present work gives an overview of developments, specifically aimed at extending the code capabilities for cleaning studies. They mainly involve: the online aperture check; the possibility to perform simulations coupled to advanced Monte Carlo codes like Fluka or using the scattering event generator of the Merlin code; the generalisation of tracking maps to ion species; the implementation of composite materials of relevance for the future upgrades of the LHC collimators; the physics of interactions with bent crystals. Plans to merge these functionalities into a single version of the SixTrack code will be outlined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB046  
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THPAB047 New Features of the 2017 SixTrack Release 3815
 
  • K.N. Sjobak, J. Barranco García, R. De Maria, E. McIntosh, A. Mereghetti
    CERN, Geneva, Switzerland
  • M. Fitterer
    Fermilab, Batavia, Illinois, USA
  • V. Gupta
    IIT, Guwahati, Assam, India
  • J. Molson
    LAL, Orsay, France
 
  The SixTrack particle tracking code is routinely used to simulate particle trajectories in high energy circular machines like the LHC and FCC, and is deployed for massive simulation campaigns on CERN clusters and on the BOINC platform within the LHC@Home volunteering computing project. The 2017 release brings many upgrades that improve flexibility, performance, and accuracy. This paper describes the new modules for wire- and electron lenses (WIRE and ELEN), the expert interface for beam-beam element (BEAM/EXPERT), the extension of the number of simultaneously tracked particles, the new Frequency Map Analysis (FMA) postprocessing option, the generation of a single zip of selected output files (ZIPF) in order to extend the coverage of the studies in LHC@HOME (e.g. FMA and on-line aperture checks), coupling to external codes (DYNK-PIPE and BDEX), a new CMAKE based build- and test mechanism, and internal restructuring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB047  
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