Keyword: beam-losses
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MOOCB01 Beam-induced Quench Tests of LHC Magnets simulation, quadrupole, collimation, experiment 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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MOPRO019 Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV simulation, proton, quadrupole, operation 105
 
  • N.V. Shetty, B. Auchmann, V. Chetvertkova, A. Lechner, A. Priebe, M. Sapinski, A.P. Verweij, D. Wollmann
    CERN, Geneva, Switzerland
 
  In 2013, beam-induced quench tests with 4 TeV protons were performed to probe the quench level of LHC arc quadrupole magnets at timescales corresponding to millisecond beam losses and steady-state losses. As the energy deposition in magnet coils cannot be measured directly, this study presents corresponding FLUKA simulations as well as estimates of quench levels derived with the QP3 code. Furthermore, beam loss monitor (BLM) signals were simulated and benchmarked against the measurements. Simulated and measured BLM signals are generally found to agree within 30 percent.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO019  
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MOPRO043 Handling 1 MW Losses with the LHC Collimation System collimation, simulation, betatron, proton 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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MOPRO109 Beam Loss Studies for the KEK Compact-ERL scattering, simulation, electron, cavity 349
 
  • O. Tanaka, T. Furuya, K. Harada, N. Nakamura, H. Sakai, M. Shimada, K. Umemori
    KEK, Ibaraki, Japan
  • E. Cenni
    Sokendai, Ibaraki, Japan
 
  Beam losses due to effects of Touschek, residual gas, intra-beam scattering, and field emission were studied for the KEK compact Energy Recovery Linac (cERL), which is now under commissioning. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beamline for the future 3GeV ERL project. The goal is to achieve a safety low-emittance and high-current beams operation which can help contribute to the beam loss study under 3GeV ERL project. We used existing and modified ELEGANT routine to perform the simulations. We also developed a MATLAB data analysis algorithm to handle the large amount of information that is outputted from the program. The data obtained then compared with the theoretical estimation to judge the computation’s accuracy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO109  
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MOPME045 Overview on the Design of the Machine Protection System for ESS target, status, neutron, proton 472
 
  • A. Nordt
    ESS, Lund, Sweden
  • A. Apollonio, R. Schmidt
    CERN, Geneva, Switzerland
 
  Scope of the Machine Protection System (MPS) for the European Spallation Source (ESS) is to protect equipment located in the accelerator, target station, neutron instruments and conventional facilities, from damage induced by beam losses or malfunctioning equipment. The MPS design function is to inhibit beam production within a few microseconds for the fastest failures at a safety integrity level of SIL2 according to the IEC61508 standard. These requirements result from a hazard and risk analysis being performed for the all systems at ESS. In a next step the architecture and topology of the distributed machine interlock system has been developed and will be presented. At the same time as MPS seeks to protect equipment it must protect the beam by avoiding triggering false stops of beam production, leading to unnecessary downtime of the ESS facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME045  
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MOPRI001 Induced Heating Power Evaluation in RIB Transfer Line of SPIRAL2 ion, solenoid, space-charge, ECR 570
 
  • N.Yu. Kazarinov
    JINR, Dubna, Moscow Region, Russia
  • D. Boutin, F.R. Osswald
    IPHC, Strasbourg Cedex 2, France
 
  Radioactive Ion Beams of SPIRAL2 project will be produced in the ECR ion source using the Helium as supporting gas. RIB transported in the transfer lines have a multi-component structure and total current of the beams is defined by Helium ions. The total power of Helium component may reach 300 W. The focusing force acting on the ions in the transfer beam line is strongly dependent on mass-to-charge ratio (this is valid for magnetic optical elements). For this reason supporting gas ions will be lost at initial part of the beam line between ECR ion source and analyzing magnet. The Helium beam losses and induced heating power density at the wall of vacuum tube in RIB transfer line of SPIRAL2 during transportation of Ar, Xe and U ion beam are evaluated in this report.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI001  
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TUPRO016 Machine Protection Challenges for HL-LHC cavity, extraction, operation, luminosity 1039
 
  • R. Schmidt, T. Bär, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
 
  LHC operation requires the flawless functioning of the machine protection systems. The energy stored in the beam was progressively increased beyond the 140 MJ range at the end of 2012 at 4 TeV/c. The further increase to 364 MJ expected for 2015 at 6.5 TeV/c should be possible with the existing protection systems. For HL-LHC, additional failure modes are considered. The stored beam energy will increase by another factor of two with respect to nominal and a factor of five more than experienced so far. The maximum beta function will increase. It is planned to install crab cavities in the LHC. With crab cavities, sudden voltage decays within 100 us after e.g. cavity quenches lead to large beam oscillations. Tracking simulations predict trajectory distortions of up to 1.5 σ in the first turn after a sudden drop of the deflecting voltage in a single cavity within 3 turns. The energy of several MJ stored in halo protons that could hit the collimator in case of such events is far above damage level, even if the collimator jaws are made of robust material. In this paper we discuss the challenges for machine protection in the HL-LHC era and possible mitigation strategies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO016  
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TUPRO059 Beam Energy Measurements using Resonant Spin Depolarization at ALBA polarization, resonance, feedback, synchrotron 1168
 
  • Z. Martí, U. Iriso, F. Pérez
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
 
  Energy measurements with precision down to 10-5 are inferred from the lifetime evolution when the beam is depolarized using AC kicks with the Transverse Fast Feedback system. Lifetime measurements are carried out using the DCCT, the BPM sum signals, pin-diode BLMs, and a scintillator based Beam Loss Detector. Results obtained with this instrumentation are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO059  
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TUPRO067 Beam Transport Optimization Studies of the PSI MW-Class Proton Channel target, proton, simulation, optics 1189
 
  • D. Reggiani, D.C. Kiselev, T. Reiss, R. Sobbia, V. Talanov, M. Wohlmuther
    PSI, Villigen PSI, Switzerland
 
  The proton channel of the PSI high intensity proton accelerator (HIPA) transports the beam from the extraction point of the ring cyclotron through two meson production graphite targets up to the SINQ spallation source. After many years of continuous improvement, the HIPA accelerator complex has now reached the remarkable beam power of 1.4 MW. The next power upgrade is foreseen for the near future. In order to achieve this further step, an optimization of the beam optics in the proton channel is required with the goal of keeping the beam losses at a reasonable extent and, at the same time improve the beam distribution on the SINQ target.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO067  
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WEPRO078 Background Calculations for the High Energy Beam Transport Region of the European Spallation Source neutron, target, photon, background 2137
 
  • R.J. Barlow, A.M. Toader
    University of Huddersfield, Huddersfield, United Kingdom
  • L. Tchelidze
    ESS, Lund, Sweden
  • H.D. Thomsen
    ISA, Aarhus, Denmark
 
  Expected backgrounds in the final accelerator-to-target region of the European Spallation Source, to be built in Lund, Sweden, have been calculated using the MCNPX program. We consider the effects of losses from the beam, both along the full length and localised at the bending magnets, and also backsplash from the target. The prompt background is calculated, and also the residual dose, as a function of time, arising from activation of the beam components. Activation of the air is also determined. The model includes the focussing and rasterising magnets, and shows the effects of the concrete walls of the tunnel. We give the implications for the design and operation of the accelerator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO078  
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WEPME040 Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN vacuum, experiment, factory, electron 2354
 
  • M.A. Gallilee, P. Chiggiato, P. Costa Pinto, L.M.A. Ferreira, P. Lepeule, J. Perez Espinos, L. Prever-Loiri, A. Sapountzis
    CERN, Geneva, Switzerland
 
  Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity LHC, the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and NEG thin-film coating.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME040  
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WEPME080 Optimization of Quadripolar Field Production for Electrostatic Ion Beam Focusing quadrupole, focusing, emittance, radioactivity 2468
 
  • F.R. Osswald, E. Bouquerel, D. Boutin
    IPHC, Strasbourg Cedex 2, France
  • W. Beeckman, J.L. Lancelot
    Sigmaphi, Vannes, France
 
  Recent calculations concerning the shape of the quadrupole used as a focusing lens revealed a potential progress margin especially for short devices*. The main issues of the paper are related with the improvement of the performances of some standard quadrupolar focusing equipments considered here with an electrostatic technology i.e. the influence on the beam transmission, aberrations limitation, and reduction of beam losses. The joint research and development programme between a laboratory and the industry are expected to enable technology transfer, design optimization and cost reduction.
* Quadrupole shapes, R. Baartman, PRST-AB 15, 074002 (2012)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME080  
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THPME047 Sorting in the ESS cavity, linac, emittance, simulation 3329
 
  • S. Peggs, E. Laface, E. Sargsyan, R. Zeng
    ESS, Lund, Sweden
 
  Sorting optical elements has significant potential during the construction of superconducting linacs like the ESS, in the same way that it has proved to be very effective in circular accelerators like RHIC and the LHC. In the linac domain, the elements of primary interest are cavities and cryomodules, instead of the magnets (of all sorts) that are routinely sorted in circular accelerators. Multiple cavities can be sorted to optimise individual cryomodules, and cryomodules can be sorted into optimised locations within the tunnel. Different sorting strategies are discussed and preliminarily evaluated in this paper. Central to the evaluation is the identification of goal (or penalty) functions that are maximised (or minimised), and which can be rapidly quantified by simulation. Also crucial is the availability of a modeling system that is realistic in its complex representation of the linac, and which can easily be modified and developed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME047  
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THPME057 Calculations of Halo in TraceWin Code emittance, diagnostics, linac, simulation 3361
 
  • N. Pichoff, P.A.P. Nghiem, D. Uriot
    CEA/DSM/IRFU, France
  • M. Valette
    CEA/IRFU, Gif-sur-Yvette, France
 
  The TraceWIN code is used to simulate the dynamics of the particles and to design linear particle accelerators. The growth of rms emittance along the accelerator is often used to estimate the quality of a design. For high beam powers, the aim is also to limit the production of halo in order to keep particle losses under a requested limit. We present in this article the different ways to quantify this halo in TraceWin.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME057  
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THPME086 Optical Fiber Beam Loss Monitor for the PHIL and ThomX Facilities radiation, vacuum, photon, operation 3433
 
  • I. Chaikovska, L. Burmistrov, N. Delerue, A. Variola
    LAL, Orsay, France
 
  Fiber beam loss monitor (FBLM) is an attractive solution to measure intensity and position of the beam losses in the real time. It is a very useful tool, especially, for the commissioning and beam alignment. In this article we report on the development of the FBLM at PHIL (PHotoinjector at LAL, Orsay, France) as a prototype of the beam loss monitor for the ThomX machine, the compact Compton based X-ray source being in the construction phase in Orsay.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME086  
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THPME154 Turn-by-turn Beam Profile Study at VEPP-4M dynamic-aperture, simulation, betatron, diagnostics 3620
 
  • O.I. Meshkov, E.B. Levichev, P.A. Piminov, A.N. Zhuravlev
    BINP SB RAS, Novosibirsk, Russia
 
  The beam dynamics during crossing of dynamical aperture border was studied. We controlled the beam losses and beam transversal profile during high-amplitude betatron oscillations caused by the electrostatic kick. The beam transversal profile was recorded by the Multi Anode Photomultiplier with turn-to turn temporal resolution. The experimental data are compared with numerical simulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME154  
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THPRI094 MadX Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation simulation, quadrupole, experiment, focusing 3991
 
  • V. Chetvertkova, B. Auchmann, T. Bär, W. Höfle, A. Priebe, M. Sapinski, R. Schmidt, A.P. Verweij, D. Wollmann
    CERN, Geneva, Switzerland
 
  Quench tests with stored beam were performed in 2013 with one of the LHC main focusing quadrupoles to experimentally verify the quench levels for beam losses in the time scales from a few milliseconds to several seconds. A novel technique combining a 3-corrector orbital bump and transverse-damper kicks was used for inducing the beam losses. MadX tracking simulations were an essential step for determining the spatial and angular beam loss distributions during the experiment. These were then used as input for further energy-deposition and quench-level calculations. In this paper the simulated beam-loss distributions for the respective time scales and experimental parameters are presented. Furthermore the sensitivity of the obtained loss-distributions to the variation of key input parameters, which were measured during the experiment, is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI094  
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