Author: Appleby, R.
Paper Title Page
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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MOPRO046 Comparison of MERLIN/SixTrack for LHC Collimation Studies 185
 
  • M. Serluca, R. Appleby, J. Molson
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, H. Rafique, A.M. Toader
    University of Huddersfield, Huddersfield, United Kingdom
  • R. Bruce, A. Marsili, S. Redaelli, B. Salvachua
    CERN, Geneva, Switzerland
  • C. Tambasco
    University of Rome La Sapienza, Rome, Italy
 
  Simulations of the LHC collimation system have been carried out in previous years with the well known SixTrack code with collimation features. MERLIN is a C++ accelerator physics library that has been extended to perform collimation studies. The main features of the code are: its modular nature, allowing the user to easily implement new physics processes such as resistive wakefields and synchrotron radiation, improved scattering routines and the MPI protocol for parallel execution. MERLIN has been configured to use the same scattering routines as SixTrack in order to benchmark the code for the LHC collimation system. In this paper we present a detailed comparison between MERLIN and SixTrack for optics and cleaning inefficiency calculation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO046  
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MOPRI049 An Ultracold Electron Facility in Manchester 714
 
  • Ö. Mete, R. Appleby, W. Bertsche, M.A. Harvey, G.X. Xia
    UMAN, Manchester, United Kingdom
  • S. Chattopadhyay
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.J. Murray
    The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
 
  An ultra-cold atom based electron source (UCAE) facility has been built in the Photon Science Institute (PSI), University of Manchester. In this paper, the key components and working principles of this source are introduced. Pre-commissioning status of this facility and the preliminary simulations results are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI049  
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MOPRI076 Simulation of Dynamics in Ultra-compact Isochronous Medium Energy Racetrack FFAGs 780
 
  • R. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • K.M. Hock
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C. Johnstone
    PAC, Batavia, Illinois, USA
 
  Funding: Research supported by STFC grant number ST/K002503/1 "Racetrack FFAGs for medical, PRISM and energy applications".
The FFAG (Fixed-Field Alternating-gradient) accelerator is a class of accelerators that comprises the best features of the cyclotron and the synchrotron, combining fixed magnetic fields with strong focusing gradients for optimal stable, low-loss operation. Here, a new type of medium-energy 1-GeV isochronous (CW) FFAG has been developed in a racetrack layout that supports two opposing synchrotron-like straights, permitting both high-gradient RF modules and efficient injection and extraction in a highly compact footprint. In this paper we present beam dynamic simulations for this compact racetrack FFAG, and compare the differences between an equivalent circular and a racetrack configuration. A comparison of the FFAG dynamics with the 800-MeV (Daeδalus) cyclotron is briefly presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI076  
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MOPRI077 Hi-Lumi LHC Collimation Studies with MERLIN Code 784
 
  • M. Serluca, R. Appleby, J. Molson
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, H. Rafique, A.M. Toader
    University of Huddersfield, Huddersfield, United Kingdom
 
  The collimation system is key to the successful operation of the LHC. Measurements and simulations of the previous run at 4 TeV have shown that the system is ready for the next step, running at 7 TeV, but at the same time some sensitive cleaning locations have been identified. In particular the dispersion suppressors downstream of the betatron cleaning region in IR7 are sensitive to single diffractive scattered protons from the collimator jaws. These particles can lead to magnet quenching. The MERLIN C++ library has been developed to exploit the functionality of an object oriented code, with improved collective effects and scattering routines. New single diffractive and elastic scattering routines, based on a fit of existing experimental data with the Regge theory of soft interactions of high energy scattering, is implemented in MERLIN. In this paper we present the impact of the new single diffractive scattering physics on the cleaning inefficiency of the LHC collimation system for the Achromatic Telescope Squeezing (ATS) PreSqueeze optics scheme, for the HL-LHC project. The results are compared with the same loss map calculated using a SixTrack+K2 like scattering routine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI077  
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MOPRI098 Design Studies of the Upgraded Collimation System in the SPS-to-LHC Transfer Lines 845
 
  • A. Mereghetti, C. Bracco, F. Cerutti, B. Goddard, J. Hrivnak, V. Kain, F.L. Maciariello, M. Meddahi, G.E. Steele
    CERN, Geneva, Switzerland
  • R. Appleby
    UMAN, Manchester, United Kingdom
 
  In the framework of the LHC Injectors Upgrade (LIU) Project, the collimators in the SPS-to-LHC transfer lines are presently under re-design, in order to cope with the unprecedented beam intensities and emittances required by the High Luminosity LHC (HL-LHC). Factors ruling the design phase are the robustness of the jaws on one side and, on the other side, the proton absorption and the emittance blow-up, essential for an effective protection of the equipment in the LHC injection regions and the LHC machine. In view of the new design, based on the one of the currently installed TCDI collimators and past investigations, the FLUKA Monte Carlo code is used to address these two factors. The present studies are intended to give essential feedback to the identification of viable solutions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI098  
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TUPRO002 Fringe Fields Modeling for the High Luminosity LHC Large Aperture Quadrupoles 993
 
  • B. Dalena, A. Chancé, O. Gabouev
    CEA/IRFU, Gif-sur-Yvette, France
  • R. Appleby, D.R. Brett
    UMAN, Manchester, United Kingdom
  • R. De Maria, M. Giovannozzi
    CERN, Geneva, Switzerland
  • J. Payet
    CEA/DSM/IRFU, France
 
  Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Analytical evaluations of detuning with amplitude and chromatic effects show that the effect is small, but not negligible. Therefore, the effect on long-term beam dynamics is evaluated via tracking simulations. Different tracking models are compared in order to provide a numerical estimate of this effect due to the proposed inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO002  
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TUPRO026 Possible Beam-beam and Levelling Scenarios for HL-LHC 1071
 
  • M.P. Crouch, R. Appleby
    UMAN, Manchester, United Kingdom
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • T. Pieloni
    CERN, Geneva, Switzerland
 
  Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The upgrade of the LHC from the current set-up to high luminosity performances will provide new challenges from the point of view of beam-beam as well as other collective effects and luminosity levelling. We present the current possibilities for doing luminosity levelling for HL-LHC. We explore the merits and drawbacks of each option and briefly discuss the operational implications. The simplest option being levelling with an offset between the two beams. In particular, we look at the possibility of using flat beams in the IPs for all the available options and investigate their benefits and drawbacks, using the code COMBI. Flat beams would allow an additional degree of freedom, with the levelling only required in one of the planes at any given IP. To this end, various scenarios are looked at, both with and without crab cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO026  
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TUPRO073 RFFAG Decay Ring for nuSTORM 1208
 
  • J.-B. Lagrange, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • R. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • Y. Mori
    Kyoto University, Research Reactor Institute, Osaka, Japan
 
  The nuSTORM facility aims to deliver neutrino beams produced from the decay of muons stored in a racetrack ring. Design of racetrack FFAG (Fixed Field Alternating Gradient) decay ring for nuSTORM project is presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO073  
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TUPRI013 Dynamic Aperture Studies of the nuSTORM FFAG Ring 1574
 
  • R. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • K.M. Hock
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J.-B. Lagrange, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
 
  Funding: Research supported by STFC grant number ST/K002503/1 "Racetrack FFAGs for medical, PRISM and energy applications".
FFAG rings with a racetrack configuration are very promising as their flexible design allow for dedicated spaces for injection/extraction, RF cavities etc. A racetrack FFAG is considered as an option for the nuSTORM facility, which aims to deliver neutrino beams produced from the decay of muons stored in a ring with long sections pointing towards detectors. In this paper we discuss the definition of dynamic aperture in these machines and use the PyZgoubi framework to compute the many turn motion in the nuSTORM ring. The roles of machine imperfections and symmetry are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI013  
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TUPRI014 Modelling and Long Term Dynamics of Crab Cavities in the LHC 1578
 
  • R. Appleby, D.R. Brett
    UMAN, Manchester, United Kingdom
  • J. Barranco García, R. De Maria, A. Grudiev, R. Tomás
    CERN, Geneva, Switzerland
 
  Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 250-300 fb-1 per year. This upgrade includes the use crab cavities to mitigate the geometric loss of luminosity arising from the beam crossing angle. The tight space constraints at the location of the cavities leads to cavity designs which are axially non-symmetric and have a potentially significant effect on the long term dynamics and dynamic aperture of the LHC. In this paper we present the current status of advanced modelling of crab cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI014  
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WEPRO100 NORMA - The Normal-Conducting, Scaling Racetrack FFAG 2198
 
  • R. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • K.M. Hock
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: Research supported by STFC grant number ST/K002503/1 "Racetrack FFAGs for medical, PRISM and energy applications".
We present a design for a 30~-~350~MeV scaling racetrack FFAG accelerator for medical application - NORMA (NOrmal-conducting Racetrack Medical Accelerator) - which utilises normal-conducting magnets. NORMA consists of 12 FDF triplet cells with a maximum drift length of  ∼ 2~m; an additional drift space inserted into two places forms a racetrack lattice with enough space for injection/extraction. Optimisation routines in PyZgoubi are used to find optimum cell parameters and working point.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO100  
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