IPAC2017 - List of Keywords (collimation)

Paper	Title	Other Keywords	Page
MOPAB001	Status of the FCC-hh Collimation System	insertion, simulation, proton, collider	64
	J. Molson, A. Faus-Golfe LAL, Orsay, France R. Bruce, M. Fiascaris, A.M. Krainer, S. Redaelli CERN, Geneva, Switzerland
	Funding: Funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305. The future circular hadron collider (FCC-hh) will have an unprecedented proton beam energy of 50 TeV, and total stored beam energy of 8.4 GJ. We discuss current developments in the collimation system design, and methods with which the challenges faced due to the high energies involved can be mitigated. Finally simulation results of new collimation system designs are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB004	Improved Protection of the Warm Magnets of the LHC Betatron Cleaning Insertion	shielding, radiation, operation, luminosity	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB006	Design and Prototyping of New CERN Collimators in the Framework of the LHC Injector Upgrade (LIU) Project and the High-Luminosity (HL-LHC) Project	impedance, dipole, proton, vacuum	80
	F.-X. Nuiry, O. Aberle, M. Bergeret, A. Bertarelli, N. Biancacci, R. Bruce, M. Calviani, F. Carra, A. Dallocchio, L. Gentini, S.S. Gilardoni, R. Illan Fiastre, I. Lamas Garcia, A. Masi, A. Perillo-Marcone, S. Pianese, S. Redaelli, E. Rigutto, B. Salvant CERN, Geneva, Switzerland
	In the framework of the Large Hadron Collider (LHC) Injectors Upgrade (LIU) and the High-Luminosity LHC (HL-LHC) Projects at CERN (European Organization for Nuclear Research, in Geneva, Switzerland), collimators in the Super Proton Synchrotron (SPS) to LHC transfer lines as well as ring collimators in the LHC will undergo important upgrades in the forthcoming years, mainly focused during the Long Shutdown 2 foreseen during 2019-2020. This contribution will detail the current design of the TCDIL collimators with a particular emphasis on the engineering developments performed on the collimator jaws, aiming at getting a stringent flatness while consid-ering also the integration of thermal shock resistant materials. The prototyping phase done at CERN will be also described. The activities ongoing to prepare the series production for other LHC collimator types (TCPPM, TCSPM, TCTPM, TCLD) will be presented, describing the role that each of these collimators play on the HL-LHC Project. A focus on the series production processes, the manufacturing and assembly technologies involved and the quality and performance assurance tests will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB007	Status of Crystal Collimation Studies at the LHC	proton, injection, beam-losses, ion	84
	R. Rossi, O. Aberle, O.O. Andreassen, M.E.J. Butcher, C.A. Dionisio Barreto, I. Lamas Garcia, A. Masi, D. Mirarchi, S. Montesano, S. Redaelli, A. Rijllart, W. Scandale, P. Serrano Galvez, G. Valentino CERN, Geneva, Switzerland F. Galluccio INFN-Napoli, Napoli, Italy
	Crystal collimation is a technique that relies on highly pure bent crystals to coherently deflect beam particles - through the channeling mechanisms - onto dedicated absorbers. Standard multi-stage collimation systems for hadron beams use amorphous materials as primary collimators and might be limited by nuclear interactions and ion fragmentation that are strongly suppressed in crystals. A crystal collimation setup was installed in the betatron cleaning insertion of the Large Hadron Collider (LHC) to demonstrate with LHC beams the feasibility of this concept and to compare its performance with that of the present system. Channeling was observed for the first time with 6.5 TeV beam and and plans for further crystal collimation beam tests at the LHC are discussed. Results of these first beam tests are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB009	Decomposition of Beam Losses at LHC	beam-losses, betatron, proton, distributed	88
	B. Salvachua, D. Mirarchi, M. Pojer, S. Redaelli, R. Rossi, G. Valentino, M. Wyszynski CERN, Geneva, Switzerland
	The LHC collimation system provides betatron cleaning and off-momentum cleaning in two different locations of the LHC ring. In the betatron cleaning area, three primary collimators cut the primary halo in horizontal, vertical and skew planes. The beam loss monitors located downstream each of these collimators can be used to diagnose the main plane of loss. We present here a method to identify these beam losses at the LHC and decompose them as a linear combination of loss scenarios using singular value decomposition to calculate Moore-Penrose pseudoinverse of the scenario matrix. This matrix has been used to evaluate the type of beam losses in different stages of the LHC cycle.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB010	Anomaly Detection for Beam Loss Maps in the Large Hadron Collider	alignment, flattop, proton, collider	92
	G. Valentino University of Malta, Information and Communication Technology, Msida, Malta R. Bruce, S. Redaelli, R. Rossi, P. Theodoropoulos CERN, Geneva, Switzerland S. Jaster-Merz University of Hamburg, Hamburg, Germany
	In the LHC, beam loss maps are used to validate collimator settings for cleaning and machine protection. This is done by monitoring the loss distribution in the ring during infrequent controlled loss map campaigns, as well as in standard operation. Due to the complexity of the system, consisting of more than 50 collimators per beam, it is difficult to identify small changes in the collimation hierarchy, which may be due to setting errors or beam orbit drifts with such methods. A technique based on Principal Component Analysis and Local Outlier Factor is presented to detect anomalies in the loss maps and therefore provide an automatic check of the collimation hierarchy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB012	Study of the 2015 Top Energy LHC Collimation Quench Tests Through an Advanced Simulation Chain	ion, simulation, proton, heavy-ion	100
	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB013	Recent Development and Results With the Merlin Tracking Code	proton, simulation, collider, electron	104
	S.C. Tygier, R.B. Appleby, H. Rafique UMAN, Manchester, United Kingdom R.J. Barlow, S. Rowan IIAA, Huddersfield, United Kingdom J. Molson LAL, Orsay, France
	Funding: Work supported by High Luminosity LHC : UK (HL-LHC-UK), grant number ST/N001621/1 MERLIN is an high performance accelerator simulation code which is used for modelling the collimation system at the LHC. It is written in extensible object-oriented C++ so new physics processes can be easily added. In this article we present recent developments needed for the Hi-Lumi LHC and future high energy colliders including FCC, such as hollow electron lenses and composite materials. We also give an overview of recent simulation work, validation against LHC data from run 1 and 2, and loss maps for Hi-Lumi LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK028	Simulation Study of Halo Collimation in the TRIUMF Ariel Proton Beam Line	proton, scattering, cyclotron, simulation	557
	F.W. Jones, R.A. Baartman, I.V. Bylinskii, Y.-N. Rao TRIUMF, Vancouver, Canada
	Funding: Funded under a contribution agreement with NRC (National Research Council of Canada). Capital funding from CFI (Canada Foundation for Innovation). The TRIUMF 500 MeV H⁻ cyclotron uses stripping foil extraction to drive several proton beam lines serving different experimental programs. As part of TRIUMF's Ariel facility now under construction, a new proton beam line 4-North will be installed to transport up to 100 microamps of 480 MeV protons to an ISOL target station for rare isotope beam production. This beam line has been designed for low-loss (< 1nA/m) operation and provides space for a collimator to remove the beam halo produced by large-angle scattering in the cyclotron extraction foil. We have studied proton loss patterns and collimation efficiency using simulation codes: the older REVMOC program and a fully 3D simulation based on Geant4, with all particle interactions in matter included. Scattering in the foil is treated by a separate iterated single-scatter model. Using these tools we arrive at a prototype design for an effective collimator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK048	Experimental Results of Crystal-Assisted Slow Extraction at the SPS	extraction, proton, detector, experiment	623
	M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, D. Mirarchi, S. Montesano, S. Petrucci, S. Redaelli, R. Rossi, W. Scandale, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland F.M. Addesa, G. Cavoto, F. Iacoangeli INFN-Roma, Roma, Italy F. Galluccio INFN-Napoli, Napoli, Italy F. Murtas INFN/LNF, Frascati (Roma), Italy
	The possibility of extracting highly energetic particles from the Super Proton Synchrotron (SPS) by means of silicon bent crystals has been explored since the 1990's. The channelling effect of a bent crystal can be used to strongly deflect primary protons and eject them from the synchrotron. Many studies and experiments have been carried out to investigate crystal channelling effects. The extraction of 120 and 270 GeV proton beams has already been demonstrated in the SPS with dedicated experiments located in the ring. Presently in the SPS, the UA9 experiment is performing studies to evaluate the possibility to use bent silicon crystals to steer particle beams in high energy accelerators. Recent studies on the feasibility of extraction from the SPS have been made using the UA9 infrastructure with a longer-term view of using crystals to help mitigate slow extraction induced activation of the SPS. In this paper, the possibility to eject particles into the extraction channel in LSS2 using the bent crystals already installed in the SPS is presented. Details of the concept, simulations and measurements carried out with beam are presented, before the outlook for the future is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK048
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK050	Reduction of Resonant Slow Extraction Losses with Shadowing of Septum Wires by a Bent Crystal	extraction, proton, simulation, septum	631
	F.M. Velotti, M.A. Fraser, B. Goddard, V. Kain, W. Scandale, L.S. Stoel CERN, Geneva, Switzerland
	A new experiment, SHiP, is being studied at CERN to investigate the existence of three Heavy Neutral Leptons in order to give experimental proof to the proposed neutrino minimal Standard Model. High-intensity slow-extraction of protons from the SPS is a pre-requisite for SHiP. The experiment requires a resonant extraction with in a 7.2 s cycle, and about 4·10¹³ protons extracted at 400 GeV in a 1 s flat-top, to achieve the needed 2·10²⁰ protons on target in five years. Although the SPS has delivered this in the past to the CNGS experiment with fast extraction, for SHiP beam losses and activation of the SPS electrostatic extraction septum (ZS) could be a serious performance limitation, since the target number of protons to resonantly extract per year is a factor of two higher than ever achieved before and a factor of four than ever reached with the third-integer slow extraction. In this paper, a novel extraction technique to significantly reduce the losses at the ZS is proposed, based on the use of a bent crystal to shadow the septum wires. Theoretical concepts are developed, the performance gain quantified and a possible layout proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK050
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK077	Impact of Dynamical Stray Fields on CLIC	shielding, luminosity, synchrotron, linear-collider	708
	E. Marín, D. Schulte CERN, Geneva, Switzerland B. Heilig MFGI, Budapest, Hungary J. Pfingstner University of Oslo, Oslo, Norway
	In this paper we estimate the tolerances of stray-fields variations on the Compact Linear Collider (CLIC), discuss possible sources and propose several solutions. The Beam Delivery System (BDS) is the most sensitive system of CLIC to unwanted magnetic field variations, already variations of 1 nT would reduce the luminosity by 10% at wavelengths comparable to the BDS without considering any correction mechanism. Two sources of magnetic field variations are considered, natural and man-made. Precise magnetic field measurements at Earth's surface under a typical geomagnetic storm are presented. Additionally, stray field measurements have been conducted at CERN, to inspect B-field variations due to technical equipment in an accelerator environment. Different solutions are proposed to minimise the impact of stray fields on the CLIC performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK077
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPVA016	ELI-NP GBS Status	laser, linac, electron, gun	880
	A. Giribono, M. Marongiu, A. Mostacci, V. Pettinacci INFN-Roma, Roma, Italy S. Albergo INFN-CT, Catania, Italy D. Alesini, M. Bellaveglia, B. Buonomo, F. Cioeta, E. Di Pasquale, G. Di Pirro, A. Esposito, A. Falone, G. Franzini, O. Frasciello, A. Gallo, S. Guiducci, S. Incremona, F. Iungo, V.L. Lollo, L. Pellegrino, L. Piersanti, S. Pioli, R. Ricci, U. Rotundo, L. Sabbatini, A. Stella, S. Tomassini, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy N. Bliss, C. Hill STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom G. Campogiani Rome University La Sapienza, Roma, Italy P. Cardarelli, M. Gambaccini INFN-Ferrara, Ferrara, Italy F. Cardelli, A. Mostacci, L. Palumbo, A. Vannozzi University of Rome La Sapienza, Rome, Italy F. Cardelli, L. Palumbo INFN-Roma1, Rome, Italy K. Cassou, K. Dupraz, A. Martens, C.F. Ndiaye, Z.F. Zomer LAL, Orsay, France G. D'Auria Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy L. Sabato U. Sannio, Benevento, Italy M. Veltri INFN-FI, Sesto Fiorentino, Italy
	New generation of Compton sources are developing in different countries to take advantage of the photon energy amplification given by the Compton backscattering effect. In this framework the Eurogammas international collaboration is producing a very high brilliance gamma source for the Nuclear Pillar of the Exterme Light Infrastructure program (ELI). At present there is a lot of effort in the mass production of all the components and in the developments and tests of the different high technology devices that will operate in the gammas beam source, like the optical recirculator and the high gradient - high average current warm C band accelerating sections. In this paper we will provide a general overview of the GBS status and of the perspectives for the future integration phase.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA016
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPIK037	Proton Cross-Talk and Losses in the Dispersion Suppressor Regions at the FCC-hh	proton, simulation, quadrupole, luminosity	1763
	H. Rafique, R.B. Appleby UMAN, Manchester, United Kingdom J.L. Abelleira JAI, Oxford, United Kingdom A.M. Krainer, A. Langner CERN, Geneva, Switzerland
	Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305 Protons that collide at the interaction points of the FCC-hh may contribute to the background in the subsequent detector. Due to the high luminosity of the proton beams this may be of concern. Using DPMJET-III to model 50 TeV proton-proton collisions, tracking studies have been performed with PTC and MERLIN in order to gauge the elastic and inelastic proton cross-talk. High arc losses, particularly in the dispersion suppressor regions, have been revealed. These losses originate mainly from particles with a momentum deviation, either from interaction with a primary collimator in the betatron cleaning insertion, or from the proton-proton collisions. This issue can be mitigated by introducing additional collimators in the dispersion suppressor region. The specific design, lattice integration, and the effect of these collimators on cross-talk is assessed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPIK075	ATF2 Beam Halo Collimation System Background and Wakefield Measurements in the 2016 Runs	wakefield, background, simulation, photon	1864
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma Sokendai, Ibaraki, Japan S. Kuroda KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain G.R. White SLAC, Menlo Park, California, USA
	A single vertical beam halo collimation system has been installed in ATF2 in March 2016 to reduce the background in the IP and Post-IP region. In this paper, we present the results of an experimental program carried out during 2016 in order to demonstrate the efficiency of the vertical collimation system and measure the wakefields induced by such a system. Furthermore, a comparison of the measurements of the collimation system wakefield impact with CST PS numerical simulations and analytical calculations is also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPVA023	Effect of Quench Heater and CLIQ Firing on the Circulating HL-LHC Beam	dipole, quadrupole, simulation, superconducting-magnet	2101
	M. Valette, L. Bortot, A.M. Fernandez Navarro, B. Lindstrom, R. Schmidt, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project. A small vertical orbit oscillation of the LHC beam was observed following a quench of a main dipole magnet. This effect was thought to be caused by the current dis-charged in the quench heater (QH) strips of the superconducting magnet and confirmed in dedicated experiments with beam in the LHC. Quench heater connection schemes with the largest effect have been identified for the LHC and its future HiLumi upgrade (HL-LHC). Furthermore, the impact on the beam following discharges of the Coupling-Loss Induced Quench (CLIQ) system, a novel technology to protect high current superconducting magnets in case of a quench, was studied to evaluate the possible failure cases.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBA1	A Comparison of Interaction Physics for Proton Collimation Systems in Current Simulation Tools	simulation, proton, collider, scattering	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 WEOBA1 [7.235 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA1
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB020	Beam Loss Simulations for the Implementation of the Hard X-Ray Self-Seeding System at European XFEL	undulator, electron, simulation, neutron	2611
	S. Liu, W. Decking, L. Fröhlich DESY, Hamburg, Germany
	The European XFEL is designed to be operated with a nominal beam energy of 17.5 GeV at a maximum repetition rate of 27000 bunches/second. The high repetition rate together with the high loss sensitivity of the undulators raises serious radiation damage concern, especially for the implementation of the Hard X-ray Self-Seeding (HXRSS) system, where a 100 um thick diamond crystal will be inserted close to the beam in the undulator section. Since the seeding power level highly depends on the delay of the electron beam with respect to the photon beam, it is crucial to define the minimum electron beam offset to the edge of the crystal in the HXRSS chicane. At European XFEL a ~200 m long post-linac collimation section has been designed to protect the undulators. In the HXRSS scheme, however, beam halo hitting the crystal can generate additional radiation. Particle tracking simulations have been performed using GEANT4 and BDSIM for the undulator and the collimation section, respectively. The critical number of electrons allowed to hit the crystal is estimated for a certain operation mode and the efficiency of beam halo collimation is investigated to predict the minimum HXRSS chicane delay.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK030	Experimental Validation of the Achromatic Telescopic Squeezing Scheme at the LHC	optics, insertion, injection, luminosity	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPVA070	Alignment and Calibration for Collimation System in CSNS/RCS	vacuum, alignment, laser, shielding	3432
	J.B. Yu, L. Dong, L. Kang, B. Li, X.J. Nie, A.X. Wang, G.Y. Wang, X.L. Wang, J.S. Zhang IHEP, Beijing, People's Republic of China J.X. Chen, T. Luo, C.J. Ning CSNS, Guangdong Province, People's Republic of China
	Funding: National Natural Science Foundation of China (Grant Nos.11375217) In order to reduce the uncontrolled losses in the localized station, the beam collimation system has been performed for the 1.6GeV synchrotron of CSNS. The CSNS/RCS transverse collimation system is designed to be a two-stage system which consists of one primary collimator and four secondary collimators. All collimators had completed processing and now been installed in the tunnel. To meet the requirements of physical system, alignment for collimation system have to be done before circulating beams. This paper will show the alignment technique of collimation system. Then some problems during the alignment process will be mentioned. For the primary collimator will be replaced in second-stage of CSNS, and the alignment for the replaced collimator will be introduced finally.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB041	Implementation of Hollow Electron Lenses in SixTrack and First Simulation Results for the HL-LHC	electron, simulation, octupole, proton	3795
	M. Fitterer, R. De Maria, S. Redaelli, K.N. Sjobak, J.F. Wagner CERN, Geneva, Switzerland G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy. Electron lenses have found a wide range of applications for hadron colliders, where the main applications are machine protection and beam-beam compensation. This paper summarizes the status of the current electron lens implementation in SixTrack with the focus on hollow electron beams for beam collimation and shows some first simulation results of the High-Luminosity upgrade of the LHC (HL-LHC).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB046	SixTrack for Cleaning Studies: 2017 Updates	ion, scattering, coupling, collider	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB047	New Features of the 2017 SixTrack Release	simulation, electron, HOM, coupling	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPIK042	The Magnetic Measurement of Conventional Magnets for Electron Beam Accelerator of Northwest Institute of Nuclear Technology	dipole, quadrupole, solenoid, electron	4190
	Z. Zhang, L. Yang IHEP, Beijing, People's Republic of China
	The project of electron beam accelerator is worked together completed by NINT (Northwest Institute of Nuclear Technology) and IHEP (Institute of High Energy Physics, China). Conventional magnet of the project includes a total of three dipole magnets, four quadrupole magnets, six solenoid magnets, and four correction magnets. All of magnets to complete the measurement by IHEP hall measuring equipment. The integrated magnetic field measurement of the arc-shaped dipole magnet requires simultaneous movement by the X-axis and the Z-axis, using Labview software written a new measurement procedure, the new measurement procedure has been completed by setting the measuring angle and the measuring radius. All measurement results of conventional magnets have reached the physical design requirements, and each magnet were carried out more than twice the measurement, the reproducibility of the measurement results are better than one-thousandth, fully meet the design claim of NINT.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPAB001

Status of the FCC-hh Collimation System

insertion, simulation, proton, collider

64

J. Molson, A. Faus-Golfe
LAL, Orsay, France
R. Bruce, M. Fiascaris, A.M. Krainer, S. Redaelli
CERN, Geneva, Switzerland

Funding: Funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305.
The future circular hadron collider (FCC-hh) will have an unprecedented proton beam energy of 50 TeV, and total stored beam energy of 8.4 GJ. We discuss current developments in the collimation system design, and methods with which the challenges faced due to the high energies involved can be mitigated. Finally simulation results of new collimation system designs are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB004

Improved Protection of the Warm Magnets of the LHC Betatron Cleaning Insertion

shielding, radiation, operation, luminosity

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB006

Design and Prototyping of New CERN Collimators in the Framework of the LHC Injector Upgrade (LIU) Project and the High-Luminosity (HL-LHC) Project

impedance, dipole, proton, vacuum

80

F.-X. Nuiry, O. Aberle, M. Bergeret, A. Bertarelli, N. Biancacci, R. Bruce, M. Calviani, F. Carra, A. Dallocchio, L. Gentini, S.S. Gilardoni, R. Illan Fiastre, I. Lamas Garcia, A. Masi, A. Perillo-Marcone, S. Pianese, S. Redaelli, E. Rigutto, B. Salvant
CERN, Geneva, Switzerland

In the framework of the Large Hadron Collider (LHC) Injectors Upgrade (LIU) and the High-Luminosity LHC (HL-LHC) Projects at CERN (European Organization for Nuclear Research, in Geneva, Switzerland), collimators in the Super Proton Synchrotron (SPS) to LHC transfer lines as well as ring collimators in the LHC will undergo important upgrades in the forthcoming years, mainly focused during the Long Shutdown 2 foreseen during 2019-2020. This contribution will detail the current design of the TCDIL collimators with a particular emphasis on the engineering developments performed on the collimator jaws, aiming at getting a stringent flatness while consid-ering also the integration of thermal shock resistant materials. The prototyping phase done at CERN will be also described. The activities ongoing to prepare the series production for other LHC collimator types (TCPPM, TCSPM, TCTPM, TCLD) will be presented, describing the role that each of these collimators play on the HL-LHC Project. A focus on the series production processes, the manufacturing and assembly technologies involved and the quality and performance assurance tests will be given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB007

Status of Crystal Collimation Studies at the LHC

proton, injection, beam-losses, ion

84

R. Rossi, O. Aberle, O.O. Andreassen, M.E.J. Butcher, C.A. Dionisio Barreto, I. Lamas Garcia, A. Masi, D. Mirarchi, S. Montesano, S. Redaelli, A. Rijllart, W. Scandale, P. Serrano Galvez, G. Valentino
CERN, Geneva, Switzerland
F. Galluccio
INFN-Napoli, Napoli, Italy

Crystal collimation is a technique that relies on highly pure bent crystals to coherently deflect beam particles - through the channeling mechanisms - onto dedicated absorbers. Standard multi-stage collimation systems for hadron beams use amorphous materials as primary collimators and might be limited by nuclear interactions and ion fragmentation that are strongly suppressed in crystals. A crystal collimation setup was installed in the betatron cleaning insertion of the Large Hadron Collider (LHC) to demonstrate with LHC beams the feasibility of this concept and to compare its performance with that of the present system. Channeling was observed for the first time with 6.5 TeV beam and and plans for further crystal collimation beam tests at the LHC are discussed. Results of these first beam tests are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB009

Decomposition of Beam Losses at LHC

beam-losses, betatron, proton, distributed

88

B. Salvachua, D. Mirarchi, M. Pojer, S. Redaelli, R. Rossi, G. Valentino, M. Wyszynski
CERN, Geneva, Switzerland

The LHC collimation system provides betatron cleaning and off-momentum cleaning in two different locations of the LHC ring. In the betatron cleaning area, three primary collimators cut the primary halo in horizontal, vertical and skew planes. The beam loss monitors located downstream each of these collimators can be used to diagnose the main plane of loss. We present here a method to identify these beam losses at the LHC and decompose them as a linear combination of loss scenarios using singular value decomposition to calculate Moore-Penrose pseudoinverse of the scenario matrix. This matrix has been used to evaluate the type of beam losses in different stages of the LHC cycle.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB010

Anomaly Detection for Beam Loss Maps in the Large Hadron Collider

alignment, flattop, proton, collider

92

G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta
R. Bruce, S. Redaelli, R. Rossi, P. Theodoropoulos
CERN, Geneva, Switzerland
S. Jaster-Merz
University of Hamburg, Hamburg, Germany

In the LHC, beam loss maps are used to validate collimator settings for cleaning and machine protection. This is done by monitoring the loss distribution in the ring during infrequent controlled loss map campaigns, as well as in standard operation. Due to the complexity of the system, consisting of more than 50 collimators per beam, it is difficult to identify small changes in the collimation hierarchy, which may be due to setting errors or beam orbit drifts with such methods. A technique based on Principal Component Analysis and Local Outlier Factor is presented to detect anomalies in the loss maps and therefore provide an automatic check of the collimation hierarchy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB012

Study of the 2015 Top Energy LHC Collimation Quench Tests Through an Advanced Simulation Chain

ion, simulation, proton, heavy-ion

100

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB013

Recent Development and Results With the Merlin Tracking Code

proton, simulation, collider, electron

104

S.C. Tygier, R.B. Appleby, H. Rafique
UMAN, Manchester, United Kingdom
R.J. Barlow, S. Rowan
IIAA, Huddersfield, United Kingdom
J. Molson
LAL, Orsay, France

Funding: Work supported by High Luminosity LHC : UK (HL-LHC-UK), grant number ST/N001621/1
MERLIN is an high performance accelerator simulation code which is used for modelling the collimation system at the LHC. It is written in extensible object-oriented C++ so new physics processes can be easily added. In this article we present recent developments needed for the Hi-Lumi LHC and future high energy colliders including FCC, such as hollow electron lenses and composite materials. We also give an overview of recent simulation work, validation against LHC data from run 1 and 2, and loss maps for Hi-Lumi LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK028

Simulation Study of Halo Collimation in the TRIUMF Ariel Proton Beam Line

proton, scattering, cyclotron, simulation

557

F.W. Jones, R.A. Baartman, I.V. Bylinskii, Y.-N. Rao
TRIUMF, Vancouver, Canada

Funding: Funded under a contribution agreement with NRC (National Research Council of Canada). Capital funding from CFI (Canada Foundation for Innovation).
The TRIUMF 500 MeV H⁻ cyclotron uses stripping foil extraction to drive several proton beam lines serving different experimental programs. As part of TRIUMF's Ariel facility now under construction, a new proton beam line 4-North will be installed to transport up to 100 microamps of 480 MeV protons to an ISOL target station for rare isotope beam production. This beam line has been designed for low-loss (< 1nA/m) operation and provides space for a collimator to remove the beam halo produced by large-angle scattering in the cyclotron extraction foil. We have studied proton loss patterns and collimation efficiency using simulation codes: the older REVMOC program and a fully 3D simulation based on Geant4, with all particle interactions in matter included. Scattering in the foil is treated by a separate iterated single-scatter model. Using these tools we arrive at a prototype design for an effective collimator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK048

Experimental Results of Crystal-Assisted Slow Extraction at the SPS

extraction, proton, detector, experiment

623

M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, D. Mirarchi, S. Montesano, S. Petrucci, S. Redaelli, R. Rossi, W. Scandale, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland
F.M. Addesa, G. Cavoto, F. Iacoangeli
INFN-Roma, Roma, Italy
F. Galluccio
INFN-Napoli, Napoli, Italy
F. Murtas
INFN/LNF, Frascati (Roma), Italy

The possibility of extracting highly energetic particles from the Super Proton Synchrotron (SPS) by means of silicon bent crystals has been explored since the 1990's. The channelling effect of a bent crystal can be used to strongly deflect primary protons and eject them from the synchrotron. Many studies and experiments have been carried out to investigate crystal channelling effects. The extraction of 120 and 270 GeV proton beams has already been demonstrated in the SPS with dedicated experiments located in the ring. Presently in the SPS, the UA9 experiment is performing studies to evaluate the possibility to use bent silicon crystals to steer particle beams in high energy accelerators. Recent studies on the feasibility of extraction from the SPS have been made using the UA9 infrastructure with a longer-term view of using crystals to help mitigate slow extraction induced activation of the SPS. In this paper, the possibility to eject particles into the extraction channel in LSS2 using the bent crystals already installed in the SPS is presented. Details of the concept, simulations and measurements carried out with beam are presented, before the outlook for the future is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK050

Reduction of Resonant Slow Extraction Losses with Shadowing of Septum Wires by a Bent Crystal

extraction, proton, simulation, septum

631

F.M. Velotti, M.A. Fraser, B. Goddard, V. Kain, W. Scandale, L.S. Stoel
CERN, Geneva, Switzerland

A new experiment, SHiP, is being studied at CERN to investigate the existence of three Heavy Neutral Leptons in order to give experimental proof to the proposed neutrino minimal Standard Model. High-intensity slow-extraction of protons from the SPS is a pre-requisite for SHiP. The experiment requires a resonant extraction with in a 7.2 s cycle, and about 4·10¹³ protons extracted at 400 GeV in a 1 s flat-top, to achieve the needed 2·10²⁰ protons on target in five years. Although the SPS has delivered this in the past to the CNGS experiment with fast extraction, for SHiP beam losses and activation of the SPS electrostatic extraction septum (ZS) could be a serious performance limitation, since the target number of protons to resonantly extract per year is a factor of two higher than ever achieved before and a factor of four than ever reached with the third-integer slow extraction. In this paper, a novel extraction technique to significantly reduce the losses at the ZS is proposed, based on the use of a bent crystal to shadow the septum wires. Theoretical concepts are developed, the performance gain quantified and a possible layout proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK077

Impact of Dynamical Stray Fields on CLIC

shielding, luminosity, synchrotron, linear-collider

708

E. Marín, D. Schulte
CERN, Geneva, Switzerland
B. Heilig
MFGI, Budapest, Hungary
J. Pfingstner
University of Oslo, Oslo, Norway

In this paper we estimate the tolerances of stray-fields variations on the Compact Linear Collider (CLIC), discuss possible sources and propose several solutions. The Beam Delivery System (BDS) is the most sensitive system of CLIC to unwanted magnetic field variations, already variations of 1 nT would reduce the luminosity by 10% at wavelengths comparable to the BDS without considering any correction mechanism. Two sources of magnetic field variations are considered, natural and man-made. Precise magnetic field measurements at Earth's surface under a typical geomagnetic storm are presented. Additionally, stray field measurements have been conducted at CERN, to inspect B-field variations due to technical equipment in an accelerator environment. Different solutions are proposed to minimise the impact of stray fields on the CLIC performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPVA016

ELI-NP GBS Status

laser, linac, electron, gun

880

A. Giribono, M. Marongiu, A. Mostacci, V. Pettinacci
INFN-Roma, Roma, Italy
S. Albergo
INFN-CT, Catania, Italy
D. Alesini, M. Bellaveglia, B. Buonomo, F. Cioeta, E. Di Pasquale, G. Di Pirro, A. Esposito, A. Falone, G. Franzini, O. Frasciello, A. Gallo, S. Guiducci, S. Incremona, F. Iungo, V.L. Lollo, L. Pellegrino, L. Piersanti, S. Pioli, R. Ricci, U. Rotundo, L. Sabbatini, A. Stella, S. Tomassini, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
N. Bliss, C. Hill
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
G. Campogiani
Rome University La Sapienza, Roma, Italy
P. Cardarelli, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
F. Cardelli, A. Mostacci, L. Palumbo, A. Vannozzi
University of Rome La Sapienza, Rome, Italy
F. Cardelli, L. Palumbo
INFN-Roma1, Rome, Italy
K. Cassou, K. Dupraz, A. Martens, C.F. Ndiaye, Z.F. Zomer
LAL, Orsay, France
G. D'Auria
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
L. Sabato
U. Sannio, Benevento, Italy
M. Veltri
INFN-FI, Sesto Fiorentino, Italy

New generation of Compton sources are developing in different countries to take advantage of the photon energy amplification given by the Compton backscattering effect. In this framework the Eurogammas international collaboration is producing a very high brilliance gamma source for the Nuclear Pillar of the Exterme Light Infrastructure program (ELI). At present there is a lot of effort in the mass production of all the components and in the developments and tests of the different high technology devices that will operate in the gammas beam source, like the optical recirculator and the high gradient - high average current warm C band accelerating sections. In this paper we will provide a general overview of the GBS status and of the perspectives for the future integration phase.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPIK037

Proton Cross-Talk and Losses in the Dispersion Suppressor Regions at the FCC-hh

proton, simulation, quadrupole, luminosity

1763

H. Rafique, R.B. Appleby
UMAN, Manchester, United Kingdom
J.L. Abelleira
JAI, Oxford, United Kingdom
A.M. Krainer, A. Langner
CERN, Geneva, Switzerland

Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305
Protons that collide at the interaction points of the FCC-hh may contribute to the background in the subsequent detector. Due to the high luminosity of the proton beams this may be of concern. Using DPMJET-III to model 50 TeV proton-proton collisions, tracking studies have been performed with PTC and MERLIN in order to gauge the elastic and inelastic proton cross-talk. High arc losses, particularly in the dispersion suppressor regions, have been revealed. These losses originate mainly from particles with a momentum deviation, either from interaction with a primary collimator in the betatron cleaning insertion, or from the proton-proton collisions. This issue can be mitigated by introducing additional collimators in the dispersion suppressor region. The specific design, lattice integration, and the effect of these collimators on cross-talk is assessed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPIK075

ATF2 Beam Halo Collimation System Background and Wakefield Measurements in the 2016 Runs

wakefield, background, simulation, photon

1864

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
Sokendai, Ibaraki, Japan
S. Kuroda
KEK, Ibaraki, Japan
I. Podadera, F. Toral
CIEMAT, Madrid, Spain
G.R. White
SLAC, Menlo Park, California, USA

A single vertical beam halo collimation system has been installed in ATF2 in March 2016 to reduce the background in the IP and Post-IP region. In this paper, we present the results of an experimental program carried out during 2016 in order to demonstrate the efficiency of the vertical collimation system and measure the wakefields induced by such a system. Furthermore, a comparison of the measurements of the collimation system wakefield impact with CST PS numerical simulations and analytical calculations is also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK075

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPVA023

Effect of Quench Heater and CLIQ Firing on the Circulating HL-LHC Beam

dipole, quadrupole, simulation, superconducting-magnet

2101

M. Valette, L. Bortot, A.M. Fernandez Navarro, B. Lindstrom, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
A small vertical orbit oscillation of the LHC beam was observed following a quench of a main dipole magnet. This effect was thought to be caused by the current dis-charged in the quench heater (QH) strips of the superconducting magnet and confirmed in dedicated experiments with beam in the LHC. Quench heater connection schemes with the largest effect have been identified for the LHC and its future HiLumi upgrade (HL-LHC). Furthermore, the impact on the beam following discharges of the Coupling-Loss Induced Quench (CLIQ) system, a novel technology to protect high current superconducting magnets in case of a quench, was studied to evaluate the possible failure cases.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBA1

A Comparison of Interaction Physics for Proton Collimation Systems in Current Simulation Tools

simulation, proton, collider, scattering

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 WEOBA1 [7.235 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA1

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB020

Beam Loss Simulations for the Implementation of the Hard X-Ray Self-Seeding System at European XFEL

undulator, electron, simulation, neutron

2611

S. Liu, W. Decking, L. Fröhlich
DESY, Hamburg, Germany

The European XFEL is designed to be operated with a nominal beam energy of 17.5 GeV at a maximum repetition rate of 27000 bunches/second. The high repetition rate together with the high loss sensitivity of the undulators raises serious radiation damage concern, especially for the implementation of the Hard X-ray Self-Seeding (HXRSS) system, where a 100 um thick diamond crystal will be inserted close to the beam in the undulator section. Since the seeding power level highly depends on the delay of the electron beam with respect to the photon beam, it is crucial to define the minimum electron beam offset to the edge of the crystal in the HXRSS chicane. At European XFEL a ~200 m long post-linac collimation section has been designed to protect the undulators. In the HXRSS scheme, however, beam halo hitting the crystal can generate additional radiation. Particle tracking simulations have been performed using GEANT4 and BDSIM for the undulator and the collimation section, respectively. The critical number of electrons allowed to hit the crystal is estimated for a certain operation mode and the efficiency of beam halo collimation is investigated to predict the minimum HXRSS chicane delay.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK030

Experimental Validation of the Achromatic Telescopic Squeezing Scheme at the LHC

optics, insertion, injection, luminosity

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPVA070

Alignment and Calibration for Collimation System in CSNS/RCS

vacuum, alignment, laser, shielding

3432

J.B. Yu, L. Dong, L. Kang, B. Li, X.J. Nie, A.X. Wang, G.Y. Wang, X.L. Wang, J.S. Zhang
IHEP, Beijing, People's Republic of China
J.X. Chen, T. Luo, C.J. Ning
CSNS, Guangdong Province, People's Republic of China

Funding: National Natural Science Foundation of China (Grant Nos.11375217)
In order to reduce the uncontrolled losses in the localized station, the beam collimation system has been performed for the 1.6GeV synchrotron of CSNS. The CSNS/RCS transverse collimation system is designed to be a two-stage system which consists of one primary collimator and four secondary collimators. All collimators had completed processing and now been installed in the tunnel. To meet the requirements of physical system, alignment for collimation system have to be done before circulating beams. This paper will show the alignment technique of collimation system. Then some problems during the alignment process will be mentioned. For the primary collimator will be replaced in second-stage of CSNS, and the alignment for the replaced collimator will be introduced finally.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB041

Implementation of Hollow Electron Lenses in SixTrack and First Simulation Results for the HL-LHC

electron, simulation, octupole, proton

3795

M. Fitterer, R. De Maria, S. Redaelli, K.N. Sjobak, J.F. Wagner
CERN, Geneva, Switzerland
G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy.
Electron lenses have found a wide range of applications for hadron colliders, where the main applications are machine protection and beam-beam compensation. This paper summarizes the status of the current electron lens implementation in SixTrack with the focus on hollow electron beams for beam collimation and shows some first simulation results of the High-Luminosity upgrade of the LHC (HL-LHC).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB046

SixTrack for Cleaning Studies: 2017 Updates

ion, scattering, coupling, collider

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB047

New Features of the 2017 SixTrack Release

simulation, electron, HOM, coupling

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPIK042

The Magnetic Measurement of Conventional Magnets for Electron Beam Accelerator of Northwest Institute of Nuclear Technology

dipole, quadrupole, solenoid, electron

4190

Z. Zhang, L. Yang
IHEP, Beijing, People's Republic of China

The project of electron beam accelerator is worked together completed by NINT (Northwest Institute of Nuclear Technology) and IHEP (Institute of High Energy Physics, China). Conventional magnet of the project includes a total of three dipole magnets, four quadrupole magnets, six solenoid magnets, and four correction magnets. All of magnets to complete the measurement by IHEP hall measuring equipment. The integrated magnetic field measurement of the arc-shaped dipole magnet requires simultaneous movement by the X-axis and the Z-axis, using Labview software written a new measurement procedure, the new measurement procedure has been completed by setting the measuring angle and the measuring radius. All measurement results of conventional magnets have reached the physical design requirements, and each magnet were carried out more than twice the measurement, the reproducibility of the measurement results are better than one-thousandth, fully meet the design claim of NINT.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)