IPAC2017 - List of Keywords (collider)

Paper	Title	Other Keywords	Page
MOYBA1	The Future of Superconducting Technology for Accelerators	SRF, cavity, superconducting-magnet, linear-collider	19
	A. Yamamoto KEK, Ibaraki, Japan
	Superconducting magnets and RF cavities are widely used in accelerators, and future accelerator projects heavily rely on this technology. There may be several questions on the future of the SC technology, concerning the feasibility of very high field dipoles (~15 T or more), possible technology evolution(s) with new materials, operation at higher temperature, and final sustainability of the technology in terms of helium procurement. The talk will cover a brief history/achievements and some interesting (future) developments, partly or fully answering these question.
	Slides MOYBA1 [25.792 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOYBA1
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MOYCA1	Ultimate Field Gradient in Metallic Structures	klystron, linac, damping, linear-collider	24
	W. Wuensch CERN, Geneva, Switzerland
	Significant progress has been made over the past decade by studies of normal-conducting linear colliders, NLC/JLC (Next/Japanese Linear Collider) and CLIC (Compact Linear Collider), to raise achievable accelerating gradient from the range of 20-30 MV/m up to 100-120 MV/m. The gain has come through a greatly increased understanding of high-power rf phenomena, development of quantitative high-gradient rf design methods, refinements in cavity fabrication techniques and through development of high peak rf power sources. Recently accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved with new techniques of conditioning in numerous prototypes at different laboratories. The talk will report on the impact of these new results on the understanding of the physics of breakdown and of conditioning, and on the ultimate gradients that can be expected in metallic RF structures.
	Slides MOYCA1 [52.087 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOYCA1
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MOPAB001	Status of the FCC-hh Collimation System	collimation, insertion, simulation, proton	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
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MOPAB010	Anomaly Detection for Beam Loss Maps in the Large Hadron Collider	collimation, alignment, flattop, proton	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.
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MOPAB013	Recent Development and Results With the Merlin Tracking Code	collimation, proton, simulation, 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
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MOPAB014	Generating Low Beta Regions With Quadrupoles for Final Muon Cooling	emittance, quadrupole, simulation, betatron	107
	J.G. Acosta, L.M. Cremaldi, T.L. Hart, S.J. Oliveros, D.J. Summers UMiss, University, Mississippi, USA D.V. Neuffer Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 Muon beams and colliders are rich sources of new physics, if muons can be cooled. A normalized rms transverse muon emittance of 280 microns has been achieved in simulation with short solenoids and a betatron function of 3 cm. Here we use ICOOL, G4beamline, and MAD-X to explore using a 400 MeV/c muon beam and strong focusing quadrupoles to approach a normalized transverse emittance of 100 microns and finish 6D muon cooling. The low beta regions produced by the quadrupoles are occupied by dense, low Z absorbers, such as lithium hydride or beryllium, that cool the beam. Equilibrium transverse emittance is linearly proportional to the beta function. Reverse emittance exchange with septa and/or wedges is then used to decrease transverse emittance from 100 to 25 microns at the expense of longitudinal emittance for a high energy lepton collider. Work remains to be done on chromaticity correction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB014
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MOPAB015	Optimization of a Skew Parametric Resonance Ionization Cooling Channel Using Genetic Algorithm	resonance, optics, controls, dipole	111
	Y. Bao UCR, Riverside, California, USA A. Afanasev GWU, Washington, USA Y.S. Derbenev, V.S. Morozov, A.V. Sy JLab, Newport News, Virginia, USA R.P. Johnson Muons, Inc, Illinois, USA
	Funding: This work is supported by Muons Inc. Skew Parametric-resonance Ionization Cooling (Skew PIC) is designed for the final 6D cooling of a high-luminosity muon collider. Tracking of muons in such a channel has been modeled in MADX and matter-dominated simulation tool G4beanline in previous studies. In this work, we developed an optimization code based on Genetic Algorithm (GA). We optimized the cooling channel and increased the acceptance of the channel by using the GA code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB015
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MOPAB107	A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure	octupole, simulation, experiment, emittance	368
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB107
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MOPAB108	Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures	octupole, wakefield, experiment, alignment	371
	J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB108
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MOPAB111	Diffraction Radiation for Non-Invasive, High-Resolution Beam Size Measurements in Future Linear Colliders	target, radiation, simulation, polarization	381
	M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland A. Aryshev, N. Terunuma KEK, Ibaraki, Japan M. Bergamaschi, P. Karataev, K.O. Kruchinin JAI, Egham, Surrey, United Kingdom M. Bergamaschi, P. Karataev, K.O. Kruchinin Royal Holloway, University of London, Surrey, United Kingdom
	Next generation linear colliders such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC) will accelerate particle beams with extremely small emittance. The high current and small size of the beam (micron-scale) due to such small emittance require non-invasive, high-resolution techniques for beam diagnostics. Diffraction Radiation (DR), a polarization radiation that appears when a charged particle moves in the vicinity of a medium, is an ideal candidate being non-invasive and allowing beams as small as a few tens of microns to be measured. Since DR is sensitive to beam parameters other than the transverse profile (e.g. its divergence and position), preparatory simulations have been performed with realistic beam parameters. A new dedicated instrument was installed in the KEK-ATF2 beam line in February 2016. At present DR is observed in the visible wavelength range, with an upgrade to the ultraviolet (200nm) planned for spring 2017 to optimize sensitivity to smaller beam sizes. Presented here are the latest results of these DR beam size measurements and simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB111
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MOPAB115	Transverse Beam Phase-Space Measurement Experience at CTF3	quadrupole, emittance, optics, linear-collider	393
	D. Gamba, B. Constance, R. Corsini, S. Döbert, L. Malina, T. Persson, J. Roberts, A.P. Rollings, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland L. Martin JAI, Oxford, United Kingdom A.L. Peirson Serratosa Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	One of the objective of the CLIC Test Facility (CTF3) at CERN is to demonstrate the CLIC Drive Beam Recombination concept. An accurate control of the transverse beam parameters is necessary in order to succeed in preserving the beam quality after the recombination. During the activity of the facility we improved our tools and technique for characterising the transverse phase space of the beam before and after recombination. The common quadrupole scan technique was improved by performing constant-beam-size measurement and it was enriched by a tomographic reconstruction of the phase-space. Moreover studies have been performed in order to estimate and subtract the impact of dispersion on such a measurements. An overview of these techniques will be presented with actual measurements performed over the last year of operations of the facility.
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MOPIK097	Vertical Dispersion and Betatron Coupling Correction for FCC-ee	emittance, quadrupole, sextupole, coupling	752
	S. Aumon, B.J. Holzer CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.
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MOPIK099	Tuning-Based Design Optimization of CLIC Final Focus System at 3 TeV	luminosity, sextupole, lattice, linear-collider	760
	F. Plassard, A. Latina, E. Marín, D. Schulte, R. Tomás CERN, Geneva, Switzerland P. Bambade LAL, Orsay, France
	The tuning aims to mitigate static imperfections of the Final Focus System (FFS) for emittance preservation at the Interaction Point (IP). A simulation campaign on the nominal CLIC FFS at 3 TeV have shown the need of rethink the design in order to ease the tuning of the machine. The goal is to optimize the lattice in order to make the FFS more tolerant to misalignments by reducing the strength of the sextupoles. The tuning efficiency is promoted as figure of merit to find the optimal layout of the FFS. A comparative study of the tuning performances have been performed for two L* options.
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MOPIK108	Tuning Simulations for the CLIC Traditional Beam Delivery System	luminosity, simulation, lattice, linear-collider	788
	R.M. Bodenstein, P. Burrows JAI, Oxford, United Kingdom E. Marín, F. Plassard, R. Tomás CERN, Geneva, Switzerland
	As the design of the CLIC Beam Delivery System (BDS) evolves, tuning simulations must be performed on each of the proposed lattice designs to see which system achieves the highest luminosity in the most realistic manner. This work will focus on the tuning simulations performed on the so-called Traditional lattice design for the center-of-mass energy of 3 TeV. The lattice modifications required to target the most important aberrations and the latest tuning results will be presented.
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MOPVA080	HOM Simulations and Damping Scheme for CEPC Cavities	HOM, cavity, damping, impedance	1052
	H.J. Zheng, J. Gao, F. Meng, P. Sha, J.Y. Zhai IHEP, Beijing, People's Republic of China
	In this paper, it will be presented that the higher order mode (HOM) analysis of the 650 MHz cavities for the Circular Electron-Positron Collider (CEPC). The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. The conventional coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe, and the propagating modes will be absorbed by the two HOM absorbers at room temperature outside the cryomodule.
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TUOCB1	Progress in the Design of Beam Optics for FCC-ee Collider Ring*	quadrupole, optics, sextupole, emittance	1281
	K. Oide, K. Ohmi KEK, Ibaraki, Japan M. Benedikt, H. Burkhardt, B.J. Holzer, A. Milanese, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland A.P. Blondel, M. Koratzinos DPNC, Genève, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia M. Boscolo INFN/LNF, Frascati (Roma), Italy
	The beam optics for the FCC-ee collider has been updated: (a) the layout is adjusted to a new footprint of FCC-hh, (b) the design around the interaction point is refined considering a number of machine-detecor interface issues, (c) the arc lattice is refined taking realistic magnet designs into account, (d) the β^* and betatron tunes are re-optimized according to recent results of the beam-beam simulations, and more. These changes make the collider design more realistic without performance degradation.
	Slides TUOCB1 [4.891 MB]
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TUPAB001	Proof of Concept of CLIC Final Focus Quadrupoles Stabilization	controls, simulation, quadrupole, ground-motion	1290
	G. Balik, B. Aimard, L. Brunetti IN2P3-LAPP, Annecy-le-Vieux, France B. Caron SYMME, Annecy-le-Vieux, France
	The Compact LInear Collider (CLIC) [1] luminosity requires extremely low beam emittances. Therefore, high beam position stability is needed to provide cen-tral collisions of the opposing bunches. Since ground motion (GM) amplitudes are likely to be larger than the required tolerances, an Active Vibration Control (AVC) system is required to damp quadrupole motion to the desired value of 0.2 nm RMS at 4 Hz. This paper focuses on the vertical final focus quadrupoles (QD0, QF1) stabilization and demonstrates its feasibility. An AVC system to be installed under QD0 and QF1 has been developed and successfully tested at LAPP. Based on a dedicated homemade sensor with an ex-tremely low internal noise level of 0.05 nm at 4 Hz, it damps GM in the frequency range [3;70] Hz by up to 30 dB, leading to RMS values of approximately 0.25 nm at 4 Hz. Simulations based on GM measured in the Compact Muon Solenoid (CMS) experimental hall [2] show that with such a GM level, the specifications would only be achieved with a Passive Insulation (PI) system, which would filter ground motion starting at ~ 25 Hz
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TUPAB010	High-Gradient Breakdown Studies of X-Band Choke-Mode Structures	cavity, linac, operation, linear-collider	1322
	X.W. Wu, H.B. Chen, J. Shi, H. Zha TUB, Beijing, People's Republic of China T. Abe, T. Higo, S. Matsumoto KEK, Ibaraki, Japan
	As an alternative design for Compact Linear Collider (CLIC) main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing-wave single-cell choke-mode damped accelerating structures working at 11.424 GHz and one reference structure without choke were designed, manufactured, low-power measured, and tuned by accelerator group at Tsinghua University. High-power test had been done on them to study the breakdown phenomenon in high gradient and how the choke affects high-gradient properties. A max gradient of 75 MV/m were achieved by the choke-mode structure and the choke breakdown limited further increasing of the gradient. Inner surface inspection of the choke-mode structures indicates that the axial part of the choke limits the performance of the structure. Based on this observation, three new choke-mode structures were designed and being manufactured.
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TUPAB110	Possible Limits of Plasma Linear Colliders	plasma, electron, scattering, emittance	1576
	F. Zimmermann CERN, Geneva, Switzerland
	Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.
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TUPIK038	Muon Sources for Particle Physics - Accomplishments of MAP	factory, experiment, proton, target	1766
	D.V. Neuffer, D. Stratakis Fermilab, Batavia, Illinois, USA M.A. Cummings Muons, Inc, Illinois, USA J.-P. Delahaye SLAC, Menlo Park, California, USA M.A. Palmer BNL, Upton, Long Island, New York, USA R.D. Ryne LBNL, Berkeley, California, USA D.J. Summers UMiss, University, Mississippi, USA
	Funding: supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy. The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a ' storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of 'e (''e) and ''' ('') beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent.
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TUPIK077	Main Achievements of the PACMAN Project for the Alignment at Micrometric Scale of Accelerator Components	alignment, quadrupole, target, feedback	1872
	H. Mainaud Durand, K. Artoos, M.C.L. Buzio, D. Caiazza, N. Catalán Lasheras, A. Cherif, I.P. Doytchinov, J.-F. Fuchs, A. Gaddi, N. Galindo Munoz, J. Gayde, S.W. Kamugasa, M. Modena, P. Novotny, S. Russenschuck, C. Sanz, G. Severino, D. Tshilumba, V. Vlachakis, M. Wendt, S. Zorzetti CERN, Geneva, Switzerland A. Faus-Golfe LAL, Orsay, France
	Funding: The research leading to these results has received funding from the European Union's 7th Framework Programme Marie Curie actions, grant agreement PITN-GA-2013-606839. The objectives of the PACMAN* project are to improve the precision and accuracy of the alignment of accelerator components. Two steps of alignment are concerned: the fiducialisation, i.e. the determination of the reference axis of components w.r.t alignment targets, and the initial alignment of components on a common support assembly. The main accelerator components considered for the study are quadrupoles, 15 GHz BPM and RF structures from the Compact LInear Collider (CLIC) project. Different methods have been developed to determine the reference axis of these components with a micrometric accuracy, as well as to determine the position of this reference axis in the coordinate frame of the common support assembly. The tools and methods developed have been validated with success on dedicated test setups using CLIC components. This paper will provide a compilation of the main achievements and results obtained. * PACMAN is an acronym for a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale.
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TUPIK097	Improving the Performance of an Orbit Feed-forward Based on Quadrupole Motion at the KEK ATF	quadrupole, kicker, feedback, ground-motion	1931
	D.R. Bett, C. Charrondière, M. Patecki, J. Pfingstner, D. Schulte, R. Tomás CERN, Geneva, Switzerland P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France K. Kubo, S. Kuroda, T. Naito, T. Okugi, T.T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	The high luminosity requirement for a future linear collider sets a demanding limit on the beam quality at the Interation Point (IP). Even the natural motion of the ground could misalign the quadrupole magnets to such an extent that the resulting dipole kicks would require compensation. The novel technique described in this paper uses seismometers to measure the positions of the quadrupole magnets in real time and a kicker to counteract the effect of their misalignment. The prototype system deployed at the Accelerator Test Facility (ATF) at KEK in Japan has already demonstrated a reduction in the pulse-to-pulse vertical position jitter of the beam by about 10%. Based on the observed correlation of the beam position to the quadrupole positions the maximum possible jitter reduction from such a system is estimated to be about 25%. This paper details the latest improvements made to the system with the aim of achieving this limit.
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TUPIK098	Micrometric Propagation of Error Using Overlapping Streched Wires for the CLIC Pre-Alignment	simulation, network, alignment, linac	1935
	H. Mainaud Durand CERN, Geneva, Switzerland J. Pfingstner University of Oslo, Oslo, Norway V. Rude ESGT-CNAM, Le Mans, France
	The geodetic network for the Compact LInear collider (CLIC) will consist of a combination of overlapping wires stretched in parallel and Wire Positioning Sensors (WPS). Such a configuration will limit the propagation of errors (maximum deviation w.r.t. a fit line) below 10 micrometres over 200 metres. These first results were obtained through simulations in 2009, with hypotheses remaining to be validated. New experimental results have been obtained allowing to reconsider the precision and accuracy of WPS sensors and the knowledge of stretched wires. This paper presents the experimental results obtained on dedicated calibration benches and on a facility made of three overlapping stretched wires over a length of 140 metres including WPS sensors measurements. It confirms the possibility to have a propagation of error below 10 micrometres using overlapping stretched wires combined with WPS sensors.
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TUPIK100	Methodology Applied for Dependability Studies on the Compact Linear Collider	simulation, operation, quadrupole, linac	1943
	O. Rey Orozko, A. Apollonio, M. Jonker CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) scheme presents several challenges in terms of reliability and availability. The goal of the study is to demonstrate the requirements for availability and reliability by identifying the key factors on failure effects and analysing possible operational scenarios and designs. Hence, a good knowledge on CLIC system structures, failure modes and failure effects is needed. This paper reports about the set-up of the studies from the definition of the CLIC failure catalogue to the implementation of the models and analysis of the results. It will present in detail the steps that need to be followed when performing such a study. Finally, the CLIC Drive Beam Quadrupoles powering system will be presented as a use-case.
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TUPIK110	Optimisation of a High-Resolution, Low-Latency Stripline Beam Position Monitor System for Use in Intra-Train Feedback	feedback, electron, extraction, cavity	1979
	N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom D.R. Bett CERN, Geneva, Switzerland
	A high-resolution, low-latency beam position monitor (BPM) system has been developed for use in feedback systems at particle accelerators and beamlines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. The fast analogue front-end signal processor is based on a single-stage RF down-mixer, with a measured latency of 15.6 ± 0.1 ns. The processor has been optimised, doubling the maximum operating beam intensity up to 1.6 nC, and the signal processing in the custom digital acquisition board has been upgraded in order to improve the resolution beyond the 300 nm level measured previously. The latest results, demonstrating a position resolution of order 150 nm with single-pass beam, will be presented.
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TUPIK111	IP Feedback Ground Motion Simulation Studies for the ILC	feedback, luminosity, ground-motion, simulation	1983
	R.M. Bodenstein, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom J. Pfingstner CERN, Geneva, Switzerland
	The International Linear Collider (ILC), as described in its Technical Design Report (TDR), must maintain strict control of its electron and positron beams in order to achieve the desired luminosity at each of its proposed center-of-mass energies. Controlling the beam parameters requires a dynamic system, capable of adjusting to a myriad of perturbations and errors. One of the components used to control the beam is the Interaction Point (IP) feedback system, which is used to dynamically steer the beams back into collision within nanoseconds. This work will show the simulation of the IP Feedback system's compensation for ground motion model K at the ILC.
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TUPVA004	Synchrotron Radiation Backgrounds for the FCC-hh Experiments	photon, simulation, radiation, optics	2031
	F. Collamati INFN-Roma1, Rome, Italy M. Boscolo INFN/LNF, Frascati (Roma), Italy H. Burkhardt, R. Kersevan CERN, Geneva, Switzerland
	Funding: This work was supported by the HORIZON 2020 project EuroCirCol, grant agreement 654305. We present in this paper a detailed analysis of the synchrotron radiation emitted by the 50 TeV protons of the FCC-hh in the last bending and quadrupole magnets upstream the interaction region. We discuss the characteristics of this radiation in terms of power, flux, photon spectrum and fans in different running conditions such as, for example, with and without crossing angle. We mainly focus our study on the fraction of photons that may hit the detector, with a full tracking into GEANT4 that simulates their interaction within the central beam pipe.
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TUPVA012	Beam Related Machine Protection of the Future Circular Collider	proton, dipole, operation, beam-losses	2063
	Y.C. Nie, M. Jonker, R. Schmidt CERN, Geneva, Switzerland
	In the Future Circular Collider (FCC) study, each nominal proton beam at top particle energy of 50 TeV has an energy of 8500 MJ, which is more than 20 times the energy of today's Large Hadron Collider (LHC) beam. Machine protection of such a high-energy and high-energy density accelerator becomes very challenging. In this paper, preliminary considerations of beam related machine protection issues of the FCC will be reported. Based on the current optics design, a few major critical equipment failures that could potentially lead to very fast (within a few turns) beam losses have been studied. The serious failure scenarios that have been considered, typically occurring at locations with high beta functions, include powering failures of normal conducting magnets, quenches of superconducting magnets as well as critical RF failures. Some fundamental questions related to the beam interlock system, e.g., the need for additional particle free abort gaps to shorten the synchronization time before executing a beam dump, will be discussed.
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TUPVA036	Cross-Talk Studies between FCC-hh Experimental Interaction Regions	detector, proton, simulation, interaction-region	2136
	J.L. Abelleira, A. Seryi JAI, Oxford, United Kingdom R.B. Appleby, H. Rafique UMAN, Manchester, United Kingdom M.I. Besana CERN, Geneva, Switzerland
	Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305. Debris from 50 TeV proton-proton collisions at the main interaction point in the FCC-hh may contribute to the background in the subsequent detector. This cross-talk is of possible concern for the FCC-hh due to the high luminosity and energy of the collider. DPMJET-III is used as a collision debris generator in order to assess the muon cross-talk contribution. An analytical calculation of muon range in rock is performed. This is followed by a full Monte Carlo simulation using FLUKA, where the accelerator tunnel has been modelled. The muon cross talk between the adjacent interaction points is assessed and its implications for FCC-hh design are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA036
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TUPVA037	FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies	optics, luminosity, quadrupole, hadron	2139
	J.L. Abelleira, E. Cruz Alaniz, A. Seryi, L. van Riesen-Haupt JAI, Oxford, United Kingdom M.I. Besana CERN, Geneva, Switzerland
	Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305. The international Future Circular Collider (FCC) study comprises the study of a new scientific structure in a tunnel of 100 km. This will allow the installation of two accelerators, a 45.6'175 GeV lepton collider and a 100-TeV hadron collider. An optimized design of a final-focus system for the hadron collider is presented here. The new design is more compact and enables unequal β^* in both planes, whose choice is justified here. This is followed by energy deposition studies, where the total dose in the magnets as a consequence of the collision debris is evaluated.
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TUPVA038	Non Linear Field Correction Effects on the Dynamic Aperture of the FCC-hh	quadrupole, lattice, interaction-region, dynamic-aperture	2143
	E. Cruz Alaniz, A. Seryi JAI, Oxford, United Kingdom E.H. Maclean, R. Martin, R. Tomás CERN, Geneva, Switzerland
	Funding: European Union's Horizon 2020 research and innovation programme under grant No 654305. The Future Circular Collider (FCC) design study aims to develop the designs of possible circular colliders in the post LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. Given the large beta functions and integrated length of the quadrupoles of the final focus triplet the effect of systematic and random non linear errors in the magnets are expected to have a severe impact on the stability of the beam. Following the experience on the HL-LHC this work explores the implementation of non-linear correctors to minimize the resonance driving terms arising from the errors of the triplet. Dynamic aperture studies are then performed to study the impact of this correction.
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TUPVA039	Effect of Alignment Errors and Orbit Correctors on the Interaction Region of the FCC-hh	quadrupole, interaction-region, optics, dipole	2147
	E. Cruz Alaniz, J.L. Abelleira, A. Seryi, L. van Riesen-Haupt JAI, Oxford, United Kingdom J.L. Abelleira, L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom
	Funding: European Union's Horizon 2020 research and innovation programme under grant No 654305. The Future Circular Collider (FCC) design study aims to develop the design of possible circular colliders in the LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. The interaction region has been designed to meet the requirements in terms of energy and luminosity. However, as it is the case in any real accelerator, misalignments in the magnets are likely to occur; the effect of these misalignments, if not properly compensated for, can jeopardize the performance of the machine. This study contemplates alignment and field errors in the interaction region in order to estimate the tolerance necessary to provide a good correction measured in terms of deviation of the orbit and strength of the correctors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA039
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TUPVA043	A Code for Optimising Triplet Layout	quadrupole, shielding, focusing, proton	2163
	L. van Riesen-Haupt, J.L. Abelleira, E. Cruz Alaniz, A. Seryi JAI, Oxford, United Kingdom
	Funding: EuroCirCol One of the main challenges when designing final focus systems of particle accelerators is maximising the beam stay clear in the strong quadrupole magnets of the inner triplet. Moreover it is desirable to keep the quadrupoles in the inner triplet as short as possible for space and costs reasons but also to reduce chromaticity and simplify corrections schemes. An algorithm that explores the triplet parameter space to optimise both these aspects was written. It uses thin lenses as a first approximation for a broad parameter scan and MADX for more precise calculations. The thin lens algorithm is significantly faster than a full scan using MADX and relatively precise at indicating the approximate area where the optimum solution lies.
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TUPVA049	Re-Visiting RHIC Snakes and Spin Orbit	injection, polarization, proton, dipole	2184
	F. Méot, R.C. Gupta, H. Huang, A. Marusic, V.H. Ranjbar, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Recent analyses of RHIC run12 to run15 proton-carbon polarimeter measurements have shown significant tilt of the polarization vector from vertical, at high energy essentially. This is confirmed by extensive measurements performed in the present Run 17. Possible origins of such large tilt may reside in snake spin rotation angle or orbit defects, to mention just two. Dedicated simulations have been undertaken to investigate possible causes, they are presented and discussed, they include the computation and use of 3-D field maps of RHIC siberian snakes.
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TUPVA127	Optimisation of the Design of the Future Circular Collider from a Civil Engineering Perspective	civil-engineering, site, lattice, alignment	2392
	J.L. Stanyard, V. Mertens, J.A. Osborne CERN, Geneva, Switzerland Y. Loo, C. Sturzaker, M. Sykes ARUP, London, United Kingdom
	This paper describes the role of civil engineering in the optimisation of the design of CERN's Future Circular Collider (FCC). The civil engineering team at CERN have employed a bespoke, interactive, geological tool to consider the suitability of multiple layout options for the FCC, situated in the Geneva Basin, in particular quasi-circular options with circumferences in the order of 100 km. The tool has been used to provide feedback on potential lattice designs that are assessed based on criteria such as geological risk, shaft depth and the environmental sensitivities of access and experimental sites. This paper presents the process and some results of the impact of civil engineering on the design of the FCC, in particular on the layout, location, and structural requirements, and also how the optimised design has been used as the basis for a cost and schedule study.
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TUPVA130	CLIC Tuning Performance Under Realistic Error Conditions	luminosity, target, linear-collider, alignment	2403
	E. Marín, A. Latina, F. Plassard, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	In this paper we present the latest results regarding the tuning study of the baseline design of the CLIC Final Focus System. In previous studies, 90% of the machines reach 90% of the nominal luminosity, when considering beam position monitor errors and transverse misalignments of magnets for a single beam case. In the present study, roll misalignments and strength errors are also included for both e^- and e⁺ beamlines, making the study a more realistic one. First, second and third order knobs are implemented in the tuning procedure to target the most relevant beam size aberrations. In order to minimise the total number of luminosity measurements a simultaneous scan of various knobs has been developed to cope with the non-fully orthogonality of the knobs. The obtained results for single and double beam studies are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA130
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WEYA1	Crab Cavity Systems for Future Colliders	cavity, luminosity, electron, proton	2474
	S. Verdú-Andrés, I. Ben-Zvi, Q. Wu BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA R. Calaga CERN, Geneva, Switzerland
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, by the US LARP program and by the HL-LHC project. KEKB was the first facility to implement the crab crossing technique in 2007, for the interaction of electron and positron beams. The High Luminosity Large Hadron Collider (HL-LHC) project envisages the use of crab cavities for increasing and levelling the luminosity of proton-proton collisions in LHC. Crab cavities have also been proposed and studied for future colliders like CLIC, ILC and eRHIC. This contribution will focus on the near and far future of crab cavities for particle colliders.
	Slides WEYA1 [6.571 MB]
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WEOBA1	A Comparison of Interaction Physics for Proton Collimation Systems in Current Simulation Tools	collimation, simulation, proton, 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]
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WEOAB3	RF Quadrupole Structures for Transverse Landau Damping in Circular Accelerators	quadrupole, damping, simulation, impedance	2516
	M. Schenk, X. Buffat, L.R. Carver, A. Grudiev, K.S.B. Li, E. Métral, K. Papke CERN, Geneva, Switzerland A. Maillard ENS, Paris, France
	The beams required for the high luminosity upgrade of the Large Hadron Collider (HL-LHC) and other potential future circular colliders (FCC) call for efficient mechanisms to suppress transverse collective instabilities. In addition to octupole magnets installed for the purpose of Landau damping in the transverse planes, we propose to use radio frequency (rf) quadrupole structures to considerably enhance the aforementioned stabilising effect. By means of the PyHEADTAIL macroparticle tracking code as well as analytical studies, the stabilising mechanism introduced by an rf quadrupole is studied and explained. It is, furthermore, compared to the influence of the second order chromaticity on transverse beam stability.
	Slides WEOAB3 [2.537 MB]
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WEPAB124	Study of Hadron-Photon Colliders for Secondary Beam Generation	photon, proton, hadron, secondary-beams	2865
	L. Serafini, C. Curatolo Istituto Nazionale di Fisica Nucleare, Milano, Italy F. Broggi INFN/LASA, Segrate (MI), Italy
	We summarize the potentialities of combining two well developed technologies, which are advancing the frontiers of hadron colliders and of light sources, namely the hadron colliders for high energy physics, and the FELs for applied and fundamental science with light, towards the generation of secondary beams with unprecedented characteristics. The collision between their typical pulses of high energy protons and X-ray photons opens a collider scenario with potentials for luminosities in excess of 10³⁸ s^-1cm^-2, adequate to generate TeV-class pion, muon, neutrino and photon beams with very high phase space densities. We report results based on Monte Carlo simulations of such a hadron-photon collider, aiming at qualifying the features of these secondary beams in view of experiments to be performed directly, or towards the design of a new kind of muon collider. C. Curatolo, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.09.002i
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WEPAB133	A Wedge Absorber Experiment at MICE	emittance, experiment, optics, scattering	2888
	D.V. Neuffer Fermilab, Batavia, Illinois, USA T.A. Mohayai IIT, Chicago, Illinois, USA C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA D.J. Summers UMiss, University, Mississippi, USA
	Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.
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WEPAB137	Cold Muonium Negative Ion Production	ion, electron, target, plasma	2898
	V.G. Dudnikov, M.A. Cummings, R.P. Johnson Muons, Inc, Illinois, USA A.V. Dudnikov BINP SB RAS, Novosibirsk, Russia
	Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.
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WEPIK001	Advanced Beam Dump for FCC-ee	simulation, electron, distributed, positron	2906
	A. Apyan ANSL, Yerevan, Armenia B. Goddard, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.
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WEPIK015	Optimized Monochromatization for Direct Higgs Production in Future Circular e⁺e⁻ Colliders	luminosity, emittance, radiation, electron	2950
	F. Zimmermann CERN, Geneva, Switzerland M.A. Valdivia García DCI-UG, León, Mexico
	Funding: This work was supported in part by the European Commission under the HORIZON2020 Integrating Activity project ARIES, grant agreement 730871, and by the Mexican CONACyT ‘‘BEAM'' Programme. Direct s-channel Higgs production in e⁺e⁻ collisions is of interest if the centre-of-mass energy spread can be reduced to be comparable to the width of the standard model Higgs boson. A monochromatization scheme could be employed in order to achieve the desired reduction, by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In high-energy high-luminosity circular colliders, beamstrahlung may increase the energy spread and bunch length. The horizontal emittance blow up due to beamstrahlung, a new effect not present in past monochromatization proposals, may degrade the performance, especially the luminosity. We study, for the FCC-ee at 62.5 GeV beam energy, how we can optimize the IP optics parameters (betax, Dx) along with the number of particles per bunch so as to obtain maximum luminosity at a desired target value of the collision energy spread.
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WEPIK016	CEPC-SppC Towards CDR	luminosity, booster, positron, detector	2954
	J. Gao IHEP, Beijing, People's Republic of China
	Funding: supported by National Key Programme for S&T Research and Development (2016YFA0400400), National Natural Science Foundation of China (11575218, 11605211, 11605210, 11505198), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH004) and CAS Center for Excellence in Particle Physics (CCEPP) In this paper we will give an introduction to Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of CEPC are described. On CEPC accelerator, the optimization of parameter designs for CEPC with different energies, machine lengthes, single ring and crab-waist collision partial double ring, advanced partial double partial ring and fully partial double ring options, etc. have been discussed systematically, and compared. CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The sub-systems of CEPC, such as collider main ring, booster, electron positron injector, etc. ave also been introduced. The detector and MDI design have been briefly mentioned. Finally, the optimization design of Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.
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WEPIK017	100 km CEPC Parameters and Lattice Design	luminosity, sextupole, dynamic-aperture, optics	2958
	D. Wang, T.J. Bian, X. Cui, J. Gao, H. Geng, Q. Qin, B. Sha, N. Wang, Y. Wang, C.H. Yu, J.Y. Zhai, C. Zhang, Y. Zhang IHEP, Beijing, People's Republic of China F. Su Institute of High Energy Physics (IHEP), People's Republic of China
	The 100km double ring configuration with shared su-perconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z ex-periment. The luminosity for Z is designed at the level of 1035 cm^-2s⁻¹. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced.
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WEPIK022	CEPC Booster Lattice Design	lattice, resonance, dynamic-aperture, booster	2968
	T.J. Bian, X. Cui, J. Gao, C. Zhang IHEP, Beijing, People's Republic of China
	In September 2012, Chinese scientists proposed a Circular Electron Positron Collider(CEPC) at 240 GeV centre of mass for Higgs studies. The CEPC booster(CEPCB) provides 120 GeV electron and positron beams to the CEPC collider for top-up injection. We foucus on the beam dynamic study for CEPCB and analyse the key point of CEPCB lattice design. In this paper, a lattice design with good dynamic aperture is proposed.
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WEPIK026	VEPP-5 Injection Complex: Two Colliders Operation Experience	injection, operation, extraction, positron	2982
	D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, M.F. Blinov, D. Bolkhovityanov, A. Butakov, E.V. Bykov, N.S. Dikansky, F.A. Emanov, A.R. Frolov, V.V. Gambaryan, K. Gorchakov, Ye.A. Gusev, S.E. Karnaev, G.V. Karpov, A.S. Kasaev, E. Kenzhebulatov, V.A. Kiselev, S. Kluschev, A.A. Kondakov, I. Koop, I.E. Korenev, N.Kh. Kot, V.R. Kozak, A.A. Krasnov, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, Yu. Maltseva, A.A. Murasev, V. Muslivets, D.A. Nikiforov, An.A. Novikov, A.V. Ottmar, A.V. Pavlenko, I.L. Pivovarov, V.V. Rashchenko, Yu. A. Rogovsky, S.L. Samoylov, N. Sazonov, A.V. Semenov, S.V. Shiyankov, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.S. Vasichev, S.V. Vasiliev, V.D. Yudin, I.M. Zemlyansky, A.N. Zhuravlev BINP SB RAS, Novosibirsk, Russia A.V. Andrianov, V.V. Balakin, F.A. Emanov, I. Koop, A.A. Krasnov, A.E. Levichev, D.A. Nikiforov, A.V. Pavlenko, Yu. A. Rogovsky, D.B. Shwartz, A.A. Starostenko NSU, Novosibirsk, Russia A.I. Mickailov Budker INP & NSU, Novosibirsk, Russia A.G. Tribendis NSTU, Novosibirsk, Russia
	Two BINP colliders VEPP-4M and VEPP-2000 e⁺e⁻ colliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP-4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK026
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WEPIK028	Status of the Electron-Positron Collider VEPP-4	electron, storage-ring, positron, experiment	2985
	P.A. Piminov BINP SB RAS, Novosibirsk, Russia
	The next phase of the e⁺e⁻ collider VEPP-4 (Budker INP, Novosibirsk) is focused on experiments in the energy range from 4 to 10 GeV (c.m.). To recover the lack of positrons at high energy a new positron source was connected to the collider. The paper discusses the facility performance with new injection and other aspects of experimental study at high energy including laser polarimeter for precise energy calibration.
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WEPIK029	High Luminosity at VEPP-2000 Collider With New Injector	luminosity, detector, injection, positron	2989
	P.Yu. Shatunov, O.V. Belikov, D.E. Berkaev, K. Gorchakov, A.S. Kasaev, A.N. Kirpotin, I. Koop, A.A. Krasnov, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, D.V. Rabusov, Yu. A. Rogovsky, A.M. Semenov, A.I. Senchenko, Y.M. Shatunov, D.B. Shwartz, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov BINP SB RAS, Novosibirsk, Russia E. Perevedentsev, Yu. A. Rogovsky, A.I. Senchenko, D.B. Shwartz NSU, Novosibirsk, Russia
	VEPP-2000 e⁺e⁻ collider at BINP was commissioned and started data taking with two detectors in 2010 with old injection chain. In the middle energy range, where the luminosity was limited by beam-beam effects, the world record values of beam-beam parameter were achieved, ksi=0.12/IP. At the same time the design luminosity value of L = 10³² cm^-2s⁻¹ at top energy (E = 1 GeV per beam) remained unreachable due to limited e⁺ production rate. The injection chain was significantly upgraded in 2013-2016. The experience of upgraded VEPP-2000 complex operation at top energies with Round Colliding Beams will be presented.
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WEPIK031	Challenges and Status of the Rapid Cycling Top-Up Booster for FCC-ee	booster, injection, synchrotron, emittance	2996
	B. Härer, S. Aumon, B.J. Holzer, Y. Papaphilippou, T. Tydecks CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	FCC-ee is a 100 km e⁺ e⁻ collider, which is being designed within the Future Circular Collider Study (FCC) for precision studies and rare decay observations in the range of 90 to 350 GeV center-of- mass energy. The beam lifetime will be limited to less than one hour, because of radiative Bhaba scattering and beamstrahlung. In order to keep the luminosity on the high level of 10³⁵ cm^-2s^-1 continuous top-up injection is required. Therefore, besides the collider, that will operate at constant energy, a fast cycling booster synchrotron will be installed in the tunnel. The injection energy to the booster synchrotron will be around 6-20 GeV. Such a small energy together with the large bending radius not only creates an ultra-small beam emittance, but also requires very low magnetic fields close to the limit of technical feasibility. This paper will focus on the challenges and requirements for the top-up booster design arising from low magnetic fields and collective instabilities and present the status of the lattice design.
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WEPIK038	Acceleration of Polarized Protons and Deuterons in the Ion Collider Ring of JLEIC	ion, resonance, polarization, proton	3014
	V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang JLab, Newport News, Virginia, USA Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider's lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of interference peaks. The beam polarization depends on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stabil-ity of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.
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WEPIK081	The Logitudinal Broadband Impedance and Energy Spread Measurements at the VEPP-4M Electron-Positron Collider	impedance, electron, synchrotron, scattering	3117
	V.M. Borin, V.A. Kiselev, G.Y. Kurkin, S.A. Nikitin, P.A. Piminov, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia V.L. Dorokhov, O.I. Meshkov BINP, Novosibirsk, Russia
	The paper presents measurements of the longitudinal broadband impedance and beam energy spread of the beam at the VEPP-4M electron-positron collider in an energy range of 1.0 - 3.5 GeV. In order to measure the longitudinal bunch size at various beam currents we used PS-1/S1 streak camera with picosecond temporal resolution. The dependence of bunch length from the bunch current at different energies demonstrates a microwave instability threshold. The bunch lengthening was caused by potential well distortion as well. Potential well distortion lengthening was used to estimate a value of the reactive part of the longitudinal impedance of the vacuum chamber of the collider Observed microwave instability thresholds was used to measure the value of the broadband impedance. The impact of the Touschek effect in the beam energy spread is discussed.
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WEPIK093	New Methods for Measurement of Nonlinear Errors in LHC Experimental IRs and Their Application in the HL-LHC	dipole, resonance, dynamic-aperture, optics	3155
	E.H. Maclean, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, M. Giovannozzi, L. Malina, T. Persson, P.K. Skowroński, R. Tomás CERN, Geneva, Switzerland
	Studies of nonlinear errors in LHC experimental insertions (IRs) during Run 1 were based upon feed-down to tune and coupling from the crossing angle orbit bumps. Useful for validating the magnetic model, this method alone is of limited use to understand discrepancies between magnetic and beam-based measurement. Feed-down from high-order multipoles is also difficult to observe. During Run 2 several alternative methods were tested in the LHC. This paper summarizes the results of these tests, and comments on their potential application to the High-Luminosity LHC upgrade.
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WEPIK114	Study of Electron Polarization Dynamics in the JLEIC at JLab	polarization, electron, simulation, synchrotron	3218
	F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. The design of an electron polarization scheme in the Jefferson Lab Electron-Ion Collider (JLEIC) aims to attain a high longitudinal electron polarization (over 70%) at collision points as required by the nuclear physics program. Comprehensive strategies for achieving this goal have been considered and developed including injection of highly polarized electrons from CEBAF, mechanisms for manipulation and preservation of the polarization in the JLEIC collider ring and measurement of the electron polarization. In particular, maintaining a sufficiently long polarization lifetime is crucial for accumulation of adequate experimental statistics. The chosen electron polarization configuration, based on the unique figure-8 geometry of the ring, removes the electron spin-tune energy dependence. This significantly simplifies the control of the electron polarization and suppresses the synchrotron sideband resonances. This paper reports recent studies and simulations of the electron polarization dynamics in the JLEIC electron collider ring.
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WEPVA024	Design of an Inductive Adder for the FCC Injection Kicker Pulse Generator	kicker, injection, impedance, high-voltage	3312
	D. Woog, M.J. Barnes, L. Ducimetière, J. Holma, T. Kramer CERN, Geneva, Switzerland
	The injection system for a 100 TeV centre-of-mass collider is an important part of the Future Circular Collider (FCC) study. Due to issues with conventional kicker systems, such as self-triggering and long term availability of thyratrons and limitations of HV-cables, innovative design changes are planned for the FCC injection kicker pulse generator. An inductive adder (IA) based on semiconductor (SC) switches is a promising technology for kicker systems. Its modular design, and the possibility of an active ripple suppression are significant advantages. Since the IA is a complex device, with multiple components whose characteristics are important, a detailed design study and construction of a prototype is necessary. This paper summarizes the system requirements and constraints, and describes the main components and design challenges of the prototype IA. It outlines the results from simulations and measurements on different magnetic core materials as well as on SC switches. The paper concludes on the design choices and progress for the prototype to be built at CERN.
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WEPVA071	Preliminary Conceptual Study of Next Generation Tau-Charm Factory at China	luminosity, factory, positron, electron	3436
	Q. Luo USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China 11375178 and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046 As BEPC II would accomplish its mission in the next decade, research on high energy science demands a successor. The luminosity of this successor should be one or two orders higher than BEPC II, while the electron beam should be longitudinal polarized at the IP. This paper discusses the feasibility and key technologies of the next tau-charm collider: a greenfield new facility or an upgrade of BEPC II.
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WEPVA087	Magnetic Measurements of NICA Booster Dipoles	dipole, booster, injection, synchrotron	3458
	V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin, M.M. Omelyanenko, M.M. Shandov JINR, Dubna, Moscow Region, Russia A.V. Shemchuk JINR/VBLHEP, Dubna, Moscow region, Russia
	NICA is a new accelerator collider complex under construction at the Joint Institute for Nuclear Research in Dubna. NICA booster magnetic system consists of 40 dipole and 48 quadrupole superconducting magnets. Measurement of magnetic field parameters is assumed for each booster magnets. At the moment 20 series dipole magnets are assembled and have passed all tests. Booster dipole magnets are 2.14 m-long, 128 /65 mm (h/v) aperture magnets with design similar to Nuclotron dipole magnet but with curved (14.1 m radius) yoke. They will produce fields up to 1.8 T. The magnetic field parameters will be measured at warm (300 K) and cold (4.5 K) conditions. This paper describes magnetic measurements methods and developing of magnetic measurements system. The obtained results of magnetic measurements of 20 magnets are summarized here.
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WEPVA089	Magnetic Measurement System for the NICA Quadrupole Magnets	quadrupole, booster, controls, superconducting-magnet	3464
	A.V. Shemchuk JINR/VBLHEP, Dubna, Moscow region, Russia V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin, M.M. Omelyanenko, M.M. Shandov JINR, Dubna, Moscow Region, Russia
	NICA is a new accelerator collider Nuclear Research (JINR) in Dubna. More than 250 superconducting magnets need for the NICA booster and collider. These magnets will be assembled and tested at the new test facility in the Laboratory of High Energy Physics JINR. A method of measuring the quality of the magnetic field in the aperture of the quadrupole magnet for the booster synchrotron is described. Commissioning of equipment for magnetic measurements in the aperture of the doublet of quadrupole lenses is described.
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WEPVA095	Preliminary Estimate of Beam Induced Power Deposition in a FCC-hh Injection Kicker Magnet	kicker, impedance, injection, coupling	3475
	A. Chmielinska, M.J. Barnes, W. Bartmann, F. Burkart, B. Goddard CERN, Geneva, Switzerland A. Chmielinska EPFL, Lausanne, Switzerland
	The Future Circular Collider for hadrons (FCC-hh) will require a fast injection kicker system that is highly reliable and that does not limit accelerator performance. Important considerations in the design of such a system are machine protection constraints, collider filling factor and hence rise and fall times of the kicker magnet field. Fast rise time kicker magnets are generally ferrite loaded transmission line type magnets with a rectangular shaped aperture. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, beam-induced heating of the ferrite yoke due to the real component of the longitudinal beam coupling impedance needs to be controlled: if the ferrite temperature exceeds the Curie point this impacts the ability to inject beam and hence the availability of the machine. This paper presents estimates for the beam induced power deposition in the ferrite yoke, based on a calculated FCC beam spectrum and an analytical model of longitudinal impedance for unshielded kicker magnets.
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WEPVA098	Measurements on a 12.5 kV Prototype Inductive Adder for the CLIC DR Extraction Kickers	flattop, kicker, extraction, damping	3487
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland
	The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely stable field pulses during injection and extraction of bunches. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. The current specifications for the modulators call for pulses with 160 ns or 900 ns flattop duration of ±12.5 kV and 305 A, with ripple of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because analogue modulation methods can be applied to adjust the output waveform. Recently, the first full-scale, 20-layer, 12.5 kV prototype inductive adder has been assembled at CERN and testing has commenced. The goal is to tailor the output waveform of the prototype to the waveform required for the DR extraction stripline kicker. The results of the initial tests and measurements are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA098
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WEPVA111	Change of Critical Current Density in Nb-Ti and Nb3Sn Strands After Millisecond Heating	superconducting-magnet, experiment, dipole, luminosity	3528
	V. Raginel, K. Kulesz, M. Mentink, R. Schmidt, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland D. Kleiven NTNU, Trondheim, Norway
	The damage mechanisms and limits of superconducting magnet components due to direct beam impact are not well understood. The energy deposition from beam losses can cause significant temperature rise and mechanical stress in the magnet coils, which can lead to a degradation of the insulation strength and critical current of the superconductor. An improved understanding of these mechanisms is not only important for the LHC in view of the planned increase in beam brightness, but also for other high energy accelerators using superconducting magnets. An experimental road map has been defined to study these damage mechanisms. Experiments have been performed with Nb-Ti and Nb3Sn strands and cable stacks at room temperature. This contribution focuses on the experimental study on the effect of millisecond heating on superconducting strands.
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WEPVA112	Characterisation of the Mechanical Behaviour of Superconducting Cables Used in High Field Magnets From Room Temperature Down to 77K	dipole, luminosity, cryogenics, superconducting-magnet	3532
	O. Sacristan De Frutos, M. Daly, P. Ferracin, C. Fichera, M. Guinchard, T. Mikkola, F. Savary, G. Vallone CERN, Geneva, Switzerland
	A comprehensive knowledge of the mechanical properties of the superconducting cable used in high-field magnets is of paramount importance to study and model the behaviour of the magnet coil from assembly to the operational conditions at cryogenic temperature. The mechanical characterisation of such kind of materials presents practical challenges associated with the heterogeneity of the materials, the geometry, size and quality of the samples that can be produced out of actual cables. These constraints impose the undertaking of such measurements from a nonstandard approach, and hence the development of tailor-made tooling. An extensive characterisation campaign for the determination of the mechanical properties of the superconducting cable at room and cryogenic temperature was launched at CERN in order to determine the most relevant mechanical properties of the superconducting cables used in the MQXF and 11T magnets. This paper describes the design of the tooling developed for this specific application as well as the experimental set-up used for the tests, and discusses the outcomes of the matrix of tests performed.
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WEPVA140	Design Studies and Optimization of High-Field Nb₃Sn Dipole Magnets for a Future Very High Energy pp Collider	dipole, magnet-design, operation, quadrupole	3597
	V.V. Kashikhin, I. Novitski, A.V. Zlobin Fermilab, Batavia, Illinois, USA
	Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy High filed accelerator magnets with operating fields of 15-16 T based on the Nb3Sn superconductor are being considered for the LHC energy upgrade or a future Very High Energy pp Collider. Magnet design studies are being conducted in the U.S., Europe and Asia to explore the limits of the Nb3Sn accelerator magnet technology while optimizing the magnet design and performance parame-ters, and reducing magnet cost. The first results of these studies performed at Fermilab in the framework of the US-MDP are reported in this paper.
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WEPVA147	Iron-Free Detector System for the Linear Collider with Multiple Return Solenoids	solenoid, detector, linear-collider, emittance	3615
	A.A. Mikhailichenko Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We investigate the Iron-free magnetic system for implementation in a detector for future Linear Collider. One peculiarity is in usage of many small-diameter solenoids for the flux return. Machine-detector interface is discussed also.
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THPAB020	Coupling Impedances and Collective Effects for FCC-ee	impedance, vacuum, collective-effects, coupling	3734
	E. Belli, M. Migliorati University of Rome La Sapienza, Rome, Italy G. Castorina, B. Spataro, M. Zobov INFN/LNF, Frascati (Roma), Italy A. Novokhatski SLAC, Menlo Park, California, USA S. Persichelli LBNL, Berkeley, California, USA
	A very important issue for the Future Circular Collider (FCC) is represented by collective effects due to the self-induced electromagnetic fields, which, acting back on the beam, could produce dangerous instabilities. In this paper we will focus our work on the FCC electron-positron machine: in particular we will study some important sources of wake fields, their coupling impedances and the impact on the beam dynamics. We will also discuss longitudinal and transverse instability thresholds, both for single bunch and multibunch, and indicate some ways to mitigate such instabilities.
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THPAB046	SixTrack for Cleaning Studies: 2017 Updates	collimation, ion, scattering, coupling	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.
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THPAB080	Estimations of Coherent Instabilities for JLEIC	electron, impedance, ion, proton	3903
	R. Li JLab, Newport News, Virginia, USA
	Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177 JLEIC is the medium energy electron-ion collider currently under active design at Jefferson Lab. The design goals of JLEIC are both high luminosity (1033-1034 cm^-2ses⁻¹) and high polarization (>70%) for the electron and light ion beams, for a wide range of electron and ion beam energies and for a wide spectrum of ion species. The unprecedented luminosity goal for this electron-ion collider sets strong requirements for the understanding and management of potential collective effects in JLEIC. In this paper, we present preliminary estimations of single and coupled bunch coherent instabilities for the electron and proton beams at collision energies for the JLEIC design. Further improvement of the estimations and mitigation methods are discussed. MEIC design summary, http://arxiv.org/ftp/arxiv/papers/1504/1504.07961.pdf, (2015).
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THPAB082	The Beam-Beam Effect and Its Consequences for the Modeling of the Jefferson Lab EIC	electron, proton, beam-beam-effects, emittance	3909
	E.W. Nissen JLab, Newport News, Virginia, USA
	Funding: Notice: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy In this work we address the effect of beam jitter on emittance growth as caused by the beam-beam effect on the Jefferson Lab Electron Ion Collider (JLEIC). This proposed collider would collide up to 100 GeV proton beams with up to 10 GeV electron beams. Due to the asymmetric rigidities of the beams and their non-linear lensing action on each other during a collision, collective effects can limit beam storage times. Using simulations we determined that one of JLEIC's synchronization concepts would require a new set of software tools to accurately understand phase space evolution.
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THPAB084	Integration of the Full-Acceptance Detector Into the JLEIC	dynamic-aperture, detector, ion, solenoid	3912
	G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y.M. Nosochkov SLAC, Menlo Park, California, USA M.-H. Wang Self Employment, Private address, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515. For physics requirements, the JLEIC (Jefferson Lab Electron Ion Collider) has a full-acceptance detector, which brings many new challenges to the beam dynamics integration. For example, asymmetric lattice and beam envelopes at interaction region (IR), forward detection, and large crossing angle with crab dynamics. Also some common problems complicate the picture, like coupling and coherent orbit from detector solenoid, high chromaticity and high multipole sensitivity from low beta-star at interaction point (IP), collision mode with different energy and ion species. Meanwhile, to get a luminosity level of a few 10³³ cm^-2ses⁻¹, small beta-star are necessary at the IP, which also means large beta in the final focus area, chromaticity correction sections, etc. This sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole components of magnets are surveyed to get a standard line. And continuously, multipole magnets as dedicated correctors are studied to provide semi-local corrections of specific multipole components beyond the standard line.
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THPAB086	Long-Term Simulations of Beam-Beam Dynamics on GPUs	GPU, simulation, beam-beam-effects, electron	3918
	B. Terzić, C.M. Cotnoir, A.L. Godunov, T. Satogata, M. Stefani ODU, Norfolk, Virginia, USA A. Arumugam, R.T. Majeti, D. Ranjan, M. Zubair ODU CS, Norfolk, Virginia, USA F. Lin, V.S. Morozov, E.W. Nissen, Y. Roblin, T. Satogata, H. Zhang JLab, Newport News, Virginia, USA
	Funding: Jefferson Lab Future machines such as the electron-ion colliders (JLEIC), linac-ring machines (eRHIC) or LHeC are particularly sensitive to beam-beam effects. This is the limiting factor for long-term stability and high luminosity reach. The complexity of the non-linear dynamics makes it challenging to perform such simulations which require millions of turns. Until recently, most of the methods used linear approximations and/or tracking for a limited number of turns. We have developed a framework which exploits a massively parallel Graphical Processing Units (GPU) architecture to allow for tracking millions of turns in a sympletic way up to an arbitrary order and colliding them at each turn. The code is called GHOST for GPU-accelerated High-Order Symplectic Tracking. As of now, there is no other code in existence that can accurately model the single-particle non-linear dynamics and the beam-beam effect at the same time for a large enough number of turns required to verify the long-term stability of a collider. Our approach relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for the beam-beam interaction.
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THPIK060	Tuning of an S-Band 10 MeV Traveling-Wave Accelerating Structure with a Non-uniform Section	impedance, network, electron, cavity	4233
	J.H. Shao, H.B. Chen, C. Gong, J. Shi, X.W. Wu, S.X. Zheng TUB, Beijing, People's Republic of China
	A tuning method of nonuniform travelling wave structures has been developed based on non-resonant perturbation measurement at Tsinghua University. The filed distribution is normalized with the shunt impedance and attenuation of each cell. Then their internal reflection can be deduced and corrected by cavity deforming. This method has been applied to an S-band 10 MeV travelling wave structure successfully. In this paper, the detailed tuning method and cold test results will be presented.
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THPIK097	High Power Tests of a Prototype X-Band Accelerating Structure for CLIC	vacuum, klystron, linac, electron	4318
	R. Zennaro, H. Blumer, M. Bopp, T. Garvey, L. Rivkin PSI, Villigen PSI, Switzerland T. Argyropoulos, D. Esperante Pereira IFIC, Valencia, Spain N. Catalán Lasheras, A. Grudiev, G. McMonagle, A. Solodko, I. Syratchev, R. Wegner, B.J. Woolley, W. Wuensch CERN, Geneva, Switzerland T.G. Lucas, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia
	Funding: Partially funded by SNF FLARE grant 20FL20₁47463 We present the design, construction and high-power test of an X-band radio-frequency accelerating structure, built as a prototype for the CERN LInear Collider (CLIC) study. X-band structures have been attracting increasing attention in recent years with applications foreseen in the domains of compact free electron lasers, medical accelerators and as diagnostics for ultra-short (femtosecond) electron bunches (when used in deflecting mode). To date, the main motivation for developments in this field has been as accelerating structures for linear colliders such as CLIC. In the context of a CERN/PSI collaboration we have built a prototype structure based on an existing CERN design, but with some modification, and following, as closely as possible, the realization and vacuum brazing techniques employed in the production of the C-band structures for the Swiss Free Electron Laser, SwissFEL. We will present the basic design of the structure and describe the fabrication process. The results of high power conditioning of the structure at CERN on an X-box test stand, to assess conditioning times, accelerating field and measure breakdown rates, will also be presented.
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THPIK105	The ZEPTO Dipole: Zero Power Tuneable Optics for CLIC	dipole, permanent-magnet, target, quadrupole	4338
	A.R. Bainbridge, J.A. Clarke, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom M. Modena CERN, Geneva, Switzerland
	Permanent magnet (PM) based systems create a significantly reduced power consumption compared to conventional room temperature electromagnets. STFC and CERN are investigating the feasibility of using tuneable PM systems to reduce high electricity and water-cooling costs; plus the associated large scale infrastructure burden in the proposed CLIC accelerator. This collaboration has previously resulted in the development of two tuneable PM Quadrupole systems. We present here a continuation of this work in the development of a pure PM C-Dipole with a tuning range of over 50%. A prototype has been simulated and constructed using a single 50x40x20 cm block of NdFeB which slides horizontally to provide tuning. We outline the design, construction and measurement of a prototype dipole and discuss its suitability as a replacement for electromagnetic systems. Issues including field homogeneity over a large tuning range and the management of high magnetic forces are addressed.
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THPVA052	Preliminary Design of Magnet Support System for CEPC	booster, dipole, quadrupole, sextupole	4557
	H. Wang, H. Qu, J.L. Wang, Z. Wang, N. Zhou IHEP, Beijing, People's Republic of China
	Magnet support system is important for CEPC. For the 100 km design of CEPC, there will be thousands of mag-nets and their supports in both collider and booster. Espe-cially, the booster ring is above the collider in the space, the magnets are hung by the supports. The goals of mag-net supports are simple and flexible structure, minimizing the magnet deformation, good stability, low cost and so on. This paper will describe the preliminary design of magnet support system, the optimization to minimize the magnet deformation and the topology optimization of the frame structure in booster.
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THPVA113	Inverse Problem-Based Magnetic Characterization of Weekly Magnetic Alloys	dipole, background, radiation, luminosity	4722
	A. Parrella, M.P. Ramos IT, Lisboa, Portugal P. Arpaia, A. Liccardo Naples University Federico II, Science and Technology Pole, Napoli, Italy M.C.L. Buzio CERN, Geneva, Switzerland
	Understanding the magnetic properties of materials used in accelerator components is becoming more and more important. For example, in the upcoming LHC upgrade at CERN, the increasing luminosity will boost the radiation dose received by the accelerator magnet's coil and consequently decrease its lifespan. Hence, a radiation shield with relative permeability less than 1.005 is required. The goal of this research is to design and validate a new method for characterizing weekly magnetic materials, suitable to be used in quality control of series production. The proposed method is based on inverse analysis approach coupled with a finite-element model. A material with unknown permeability is inserted in the air gap of a dipole magnet and the consequent perturbations of the dipole background flux density are measured. The magnetic permeability is then identified through gray-box inverse modelling, based on a finite-element approach. The results have been used to predict the magnetic impact of the radiation shield and develop further research on this subject.
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FRYCA1	The Future of High-energy Accelerators	electron, proton, hadron, positron	4856
	J. Mnich DESY, Hamburg, Germany
	The physics results from high energy colliders, neutrino experiments and from experiments in space are changing the particle physics landscape. In the last decade several accelerator designs and studies have taken shape and reached a high level of maturity both at the high energy and high intensity frontiers. The talk should review the physics questions facing the HEP community and the strategy to address them in view of the next update of the European Strategy for Particle Physics.
	Slides FRYCA1 [9.087 MB]
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Paper

Title

Other Keywords

Page

MOYBA1

The Future of Superconducting Technology for Accelerators

SRF, cavity, superconducting-magnet, linear-collider

19

A. Yamamoto
KEK, Ibaraki, Japan

Superconducting magnets and RF cavities are widely used in accelerators, and future accelerator projects heavily rely on this technology. There may be several questions on the future of the SC technology, concerning the feasibility of very high field dipoles (~15 T or more), possible technology evolution(s) with new materials, operation at higher temperature, and final sustainability of the technology in terms of helium procurement. The talk will cover a brief history/achievements and some interesting (future) developments, partly or fully answering these question.

Slides MOYBA1 [25.792 MB]

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MOYCA1

Ultimate Field Gradient in Metallic Structures

klystron, linac, damping, linear-collider

24

W. Wuensch
CERN, Geneva, Switzerland

Significant progress has been made over the past decade by studies of normal-conducting linear colliders, NLC/JLC (Next/Japanese Linear Collider) and CLIC (Compact Linear Collider), to raise achievable accelerating gradient from the range of 20-30 MV/m up to 100-120 MV/m. The gain has come through a greatly increased understanding of high-power rf phenomena, development of quantitative high-gradient rf design methods, refinements in cavity fabrication techniques and through development of high peak rf power sources. Recently accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved with new techniques of conditioning in numerous prototypes at different laboratories. The talk will report on the impact of these new results on the understanding of the physics of breakdown and of conditioning, and on the ultimate gradients that can be expected in metallic RF structures.

Slides MOYCA1 [52.087 MB]

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MOPAB001

Status of the FCC-hh Collimation System

collimation, insertion, simulation, proton

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.

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MOPAB010

Anomaly Detection for Beam Loss Maps in the Large Hadron Collider

collimation, alignment, flattop, proton

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.

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MOPAB013

Recent Development and Results With the Merlin Tracking Code

collimation, proton, simulation, 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.

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MOPAB014

Generating Low Beta Regions With Quadrupoles for Final Muon Cooling

emittance, quadrupole, simulation, betatron

107

J.G. Acosta, L.M. Cremaldi, T.L. Hart, S.J. Oliveros, D.J. Summers
UMiss, University, Mississippi, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359
Muon beams and colliders are rich sources of new physics, if muons can be cooled. A normalized rms transverse muon emittance of 280 microns has been achieved in simulation with short solenoids and a betatron function of 3 cm. Here we use ICOOL, G4beamline, and MAD-X to explore using a 400 MeV/c muon beam and strong focusing quadrupoles to approach a normalized transverse emittance of 100 microns and finish 6D muon cooling. The low beta regions produced by the quadrupoles are occupied by dense, low Z absorbers, such as lithium hydride or beryllium, that cool the beam. Equilibrium transverse emittance is linearly proportional to the beta function. Reverse emittance exchange with septa and/or wedges is then used to decrease transverse emittance from 100 to 25 microns at the expense of longitudinal emittance for a high energy lepton collider. Work remains to be done on chromaticity correction.

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MOPAB015

Optimization of a Skew Parametric Resonance Ionization Cooling Channel Using Genetic Algorithm

resonance, optics, controls, dipole

111

Y. Bao
UCR, Riverside, California, USA
A. Afanasev
GWU, Washington, USA
Y.S. Derbenev, V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: This work is supported by Muons Inc.
Skew Parametric-resonance Ionization Cooling (Skew PIC) is designed for the final 6D cooling of a high-luminosity muon collider. Tracking of muons in such a channel has been modeled in MADX and matter-dominated simulation tool G4beanline in previous studies. In this work, we developed an optimization code based on Genetic Algorithm (GA). We optimized the cooling channel and increased the acceptance of the channel by using the GA code.

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MOPAB107

A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure

octupole, simulation, experiment, emittance

368

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.

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MOPAB108

Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures

octupole, wakefield, experiment, alignment

371

J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.

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MOPAB111

Diffraction Radiation for Non-Invasive, High-Resolution Beam Size Measurements in Future Linear Colliders

target, radiation, simulation, polarization

381

M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
A. Aryshev, N. Terunuma
KEK, Ibaraki, Japan
M. Bergamaschi, P. Karataev, K.O. Kruchinin
JAI, Egham, Surrey, United Kingdom
M. Bergamaschi, P. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom

Next generation linear colliders such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC) will accelerate particle beams with extremely small emittance. The high current and small size of the beam (micron-scale) due to such small emittance require non-invasive, high-resolution techniques for beam diagnostics. Diffraction Radiation (DR), a polarization radiation that appears when a charged particle moves in the vicinity of a medium, is an ideal candidate being non-invasive and allowing beams as small as a few tens of microns to be measured. Since DR is sensitive to beam parameters other than the transverse profile (e.g. its divergence and position), preparatory simulations have been performed with realistic beam parameters. A new dedicated instrument was installed in the KEK-ATF2 beam line in February 2016. At present DR is observed in the visible wavelength range, with an upgrade to the ultraviolet (200nm) planned for spring 2017 to optimize sensitivity to smaller beam sizes. Presented here are the latest results of these DR beam size measurements and simulations.

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MOPAB115

Transverse Beam Phase-Space Measurement Experience at CTF3

quadrupole, emittance, optics, linear-collider

393

D. Gamba, B. Constance, R. Corsini, S. Döbert, L. Malina, T. Persson, J. Roberts, A.P. Rollings, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
L. Martin
JAI, Oxford, United Kingdom
A.L. Peirson Serratosa
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

One of the objective of the CLIC Test Facility (CTF3) at CERN is to demonstrate the CLIC Drive Beam Recombination concept. An accurate control of the transverse beam parameters is necessary in order to succeed in preserving the beam quality after the recombination. During the activity of the facility we improved our tools and technique for characterising the transverse phase space of the beam before and after recombination. The common quadrupole scan technique was improved by performing constant-beam-size measurement and it was enriched by a tomographic reconstruction of the phase-space. Moreover studies have been performed in order to estimate and subtract the impact of dispersion on such a measurements. An overview of these techniques will be presented with actual measurements performed over the last year of operations of the facility.

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MOPIK097

Vertical Dispersion and Betatron Coupling Correction for FCC-ee

emittance, quadrupole, sextupole, coupling

752

S. Aumon, B.J. Holzer
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.

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MOPIK099

Tuning-Based Design Optimization of CLIC Final Focus System at 3 TeV

luminosity, sextupole, lattice, linear-collider

760

F. Plassard, A. Latina, E. Marín, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
P. Bambade
LAL, Orsay, France

The tuning aims to mitigate static imperfections of the Final Focus System (FFS) for emittance preservation at the Interaction Point (IP). A simulation campaign on the nominal CLIC FFS at 3 TeV have shown the need of rethink the design in order to ease the tuning of the machine. The goal is to optimize the lattice in order to make the FFS more tolerant to misalignments by reducing the strength of the sextupoles. The tuning efficiency is promoted as figure of merit to find the optimal layout of the FFS. A comparative study of the tuning performances have been performed for two L* options.

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MOPIK108

Tuning Simulations for the CLIC Traditional Beam Delivery System

luminosity, simulation, lattice, linear-collider

788

R.M. Bodenstein, P. Burrows
JAI, Oxford, United Kingdom
E. Marín, F. Plassard, R. Tomás
CERN, Geneva, Switzerland

As the design of the CLIC Beam Delivery System (BDS) evolves, tuning simulations must be performed on each of the proposed lattice designs to see which system achieves the highest luminosity in the most realistic manner. This work will focus on the tuning simulations performed on the so-called Traditional lattice design for the center-of-mass energy of 3 TeV. The lattice modifications required to target the most important aberrations and the latest tuning results will be presented.

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MOPVA080

HOM Simulations and Damping Scheme for CEPC Cavities

HOM, cavity, damping, impedance

1052

H.J. Zheng, J. Gao, F. Meng, P. Sha, J.Y. Zhai
IHEP, Beijing, People's Republic of China

In this paper, it will be presented that the higher order mode (HOM) analysis of the 650 MHz cavities for the Circular Electron-Positron Collider (CEPC). The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. The conventional coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe, and the propagating modes will be absorbed by the two HOM absorbers at room temperature outside the cryomodule.

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TUOCB1

Progress in the Design of Beam Optics for FCC-ee Collider Ring*

quadrupole, optics, sextupole, emittance

1281

K. Oide, K. Ohmi
KEK, Ibaraki, Japan
M. Benedikt, H. Burkhardt, B.J. Holzer, A. Milanese, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
A.P. Blondel, M. Koratzinos
DPNC, Genève, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
M. Boscolo
INFN/LNF, Frascati (Roma), Italy

The beam optics for the FCC-ee collider has been updated: (a) the layout is adjusted to a new footprint of FCC-hh, (b) the design around the interaction point is refined considering a number of machine-detecor interface issues, (c) the arc lattice is refined taking realistic magnet designs into account, (d) the β^* and betatron tunes are re-optimized according to recent results of the beam-beam simulations, and more. These changes make the collider design more realistic without performance degradation.

Slides TUOCB1 [4.891 MB]

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TUPAB001

Proof of Concept of CLIC Final Focus Quadrupoles Stabilization

controls, simulation, quadrupole, ground-motion

1290

G. Balik, B. Aimard, L. Brunetti
IN2P3-LAPP, Annecy-le-Vieux, France
B. Caron
SYMME, Annecy-le-Vieux, France

The Compact LInear Collider (CLIC) [1] luminosity requires extremely low beam emittances. Therefore, high beam position stability is needed to provide cen-tral collisions of the opposing bunches. Since ground motion (GM) amplitudes are likely to be larger than the required tolerances, an Active Vibration Control (AVC) system is required to damp quadrupole motion to the desired value of 0.2 nm RMS at 4 Hz. This paper focuses on the vertical final focus quadrupoles (QD0, QF1) stabilization and demonstrates its feasibility. An AVC system to be installed under QD0 and QF1 has been developed and successfully tested at LAPP. Based on a dedicated homemade sensor with an ex-tremely low internal noise level of 0.05 nm at 4 Hz, it damps GM in the frequency range [3;70] Hz by up to 30 dB, leading to RMS values of approximately 0.25 nm at 4 Hz. Simulations based on GM measured in the Compact Muon Solenoid (CMS) experimental hall [2] show that with such a GM level, the specifications would only be achieved with a Passive Insulation (PI) system, which would filter ground motion starting at ~ 25 Hz

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TUPAB010

High-Gradient Breakdown Studies of X-Band Choke-Mode Structures

cavity, linac, operation, linear-collider

1322

X.W. Wu, H.B. Chen, J. Shi, H. Zha
TUB, Beijing, People's Republic of China
T. Abe, T. Higo, S. Matsumoto
KEK, Ibaraki, Japan

As an alternative design for Compact Linear Collider (CLIC) main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing-wave single-cell choke-mode damped accelerating structures working at 11.424 GHz and one reference structure without choke were designed, manufactured, low-power measured, and tuned by accelerator group at Tsinghua University. High-power test had been done on them to study the breakdown phenomenon in high gradient and how the choke affects high-gradient properties. A max gradient of 75 MV/m were achieved by the choke-mode structure and the choke breakdown limited further increasing of the gradient. Inner surface inspection of the choke-mode structures indicates that the axial part of the choke limits the performance of the structure. Based on this observation, three new choke-mode structures were designed and being manufactured.

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TUPAB110

Possible Limits of Plasma Linear Colliders

plasma, electron, scattering, emittance

1576

F. Zimmermann
CERN, Geneva, Switzerland

Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.

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TUPIK038

Muon Sources for Particle Physics - Accomplishments of MAP

factory, experiment, proton, target

1766

D.V. Neuffer, D. Stratakis
Fermilab, Batavia, Illinois, USA
M.A. Cummings
Muons, Inc, Illinois, USA
J.-P. Delahaye
SLAC, Menlo Park, California, USA
M.A. Palmer
BNL, Upton, Long Island, New York, USA
R.D. Ryne
LBNL, Berkeley, California, USA
D.J. Summers
UMiss, University, Mississippi, USA

Funding: supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a ' storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of 'e (''e) and ''' ('') beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent.

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TUPIK077

Main Achievements of the PACMAN Project for the Alignment at Micrometric Scale of Accelerator Components

alignment, quadrupole, target, feedback

1872

H. Mainaud Durand, K. Artoos, M.C.L. Buzio, D. Caiazza, N. Catalán Lasheras, A. Cherif, I.P. Doytchinov, J.-F. Fuchs, A. Gaddi, N. Galindo Munoz, J. Gayde, S.W. Kamugasa, M. Modena, P. Novotny, S. Russenschuck, C. Sanz, G. Severino, D. Tshilumba, V. Vlachakis, M. Wendt, S. Zorzetti
CERN, Geneva, Switzerland
A. Faus-Golfe
LAL, Orsay, France

Funding: The research leading to these results has received funding from the European Union's 7th Framework Programme Marie Curie actions, grant agreement PITN-GA-2013-606839.
The objectives of the PACMAN* project are to improve the precision and accuracy of the alignment of accelerator components. Two steps of alignment are concerned: the fiducialisation, i.e. the determination of the reference axis of components w.r.t alignment targets, and the initial alignment of components on a common support assembly. The main accelerator components considered for the study are quadrupoles, 15 GHz BPM and RF structures from the Compact LInear Collider (CLIC) project. Different methods have been developed to determine the reference axis of these components with a micrometric accuracy, as well as to determine the position of this reference axis in the coordinate frame of the common support assembly. The tools and methods developed have been validated with success on dedicated test setups using CLIC components. This paper will provide a compilation of the main achievements and results obtained.
* PACMAN is an acronym for a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale.

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TUPIK097

Improving the Performance of an Orbit Feed-forward Based on Quadrupole Motion at the KEK ATF

quadrupole, kicker, feedback, ground-motion

1931

D.R. Bett, C. Charrondière, M. Patecki, J. Pfingstner, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom
A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T.T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

The high luminosity requirement for a future linear collider sets a demanding limit on the beam quality at the Interation Point (IP). Even the natural motion of the ground could misalign the quadrupole magnets to such an extent that the resulting dipole kicks would require compensation. The novel technique described in this paper uses seismometers to measure the positions of the quadrupole magnets in real time and a kicker to counteract the effect of their misalignment. The prototype system deployed at the Accelerator Test Facility (ATF) at KEK in Japan has already demonstrated a reduction in the pulse-to-pulse vertical position jitter of the beam by about 10%. Based on the observed correlation of the beam position to the quadrupole positions the maximum possible jitter reduction from such a system is estimated to be about 25%. This paper details the latest improvements made to the system with the aim of achieving this limit.

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TUPIK098

Micrometric Propagation of Error Using Overlapping Streched Wires for the CLIC Pre-Alignment

simulation, network, alignment, linac

1935

H. Mainaud Durand
CERN, Geneva, Switzerland
J. Pfingstner
University of Oslo, Oslo, Norway
V. Rude
ESGT-CNAM, Le Mans, France

The geodetic network for the Compact LInear collider (CLIC) will consist of a combination of overlapping wires stretched in parallel and Wire Positioning Sensors (WPS). Such a configuration will limit the propagation of errors (maximum deviation w.r.t. a fit line) below 10 micrometres over 200 metres. These first results were obtained through simulations in 2009, with hypotheses remaining to be validated. New experimental results have been obtained allowing to reconsider the precision and accuracy of WPS sensors and the knowledge of stretched wires. This paper presents the experimental results obtained on dedicated calibration benches and on a facility made of three overlapping stretched wires over a length of 140 metres including WPS sensors measurements. It confirms the possibility to have a propagation of error below 10 micrometres using overlapping stretched wires combined with WPS sensors.

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TUPIK100

Methodology Applied for Dependability Studies on the Compact Linear Collider

simulation, operation, quadrupole, linac

1943

O. Rey Orozko, A. Apollonio, M. Jonker
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) scheme presents several challenges in terms of reliability and availability. The goal of the study is to demonstrate the requirements for availability and reliability by identifying the key factors on failure effects and analysing possible operational scenarios and designs. Hence, a good knowledge on CLIC system structures, failure modes and failure effects is needed. This paper reports about the set-up of the studies from the definition of the CLIC failure catalogue to the implementation of the models and analysis of the results. It will present in detail the steps that need to be followed when performing such a study. Finally, the CLIC Drive Beam Quadrupoles powering system will be presented as a use-case.

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TUPIK110

Optimisation of a High-Resolution, Low-Latency Stripline Beam Position Monitor System for Use in Intra-Train Feedback

feedback, electron, extraction, cavity

1979

N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland

A high-resolution, low-latency beam position monitor (BPM) system has been developed for use in feedback systems at particle accelerators and beamlines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. The fast analogue front-end signal processor is based on a single-stage RF down-mixer, with a measured latency of 15.6 ± 0.1 ns. The processor has been optimised, doubling the maximum operating beam intensity up to 1.6 nC, and the signal processing in the custom digital acquisition board has been upgraded in order to improve the resolution beyond the 300 nm level measured previously. The latest results, demonstrating a position resolution of order 150 nm with single-pass beam, will be presented.

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TUPIK111

IP Feedback Ground Motion Simulation Studies for the ILC

feedback, luminosity, ground-motion, simulation

1983

R.M. Bodenstein, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
J. Pfingstner
CERN, Geneva, Switzerland

The International Linear Collider (ILC), as described in its Technical Design Report (TDR), must maintain strict control of its electron and positron beams in order to achieve the desired luminosity at each of its proposed center-of-mass energies. Controlling the beam parameters requires a dynamic system, capable of adjusting to a myriad of perturbations and errors. One of the components used to control the beam is the Interaction Point (IP) feedback system, which is used to dynamically steer the beams back into collision within nanoseconds. This work will show the simulation of the IP Feedback system's compensation for ground motion model K at the ILC.

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TUPVA004

Synchrotron Radiation Backgrounds for the FCC-hh Experiments

photon, simulation, radiation, optics

2031

F. Collamati
INFN-Roma1, Rome, Italy
M. Boscolo
INFN/LNF, Frascati (Roma), Italy
H. Burkhardt, R. Kersevan
CERN, Geneva, Switzerland

Funding: This work was supported by the HORIZON 2020 project EuroCirCol, grant agreement 654305.
We present in this paper a detailed analysis of the synchrotron radiation emitted by the 50 TeV protons of the FCC-hh in the last bending and quadrupole magnets upstream the interaction region. We discuss the characteristics of this radiation in terms of power, flux, photon spectrum and fans in different running conditions such as, for example, with and without crossing angle. We mainly focus our study on the fraction of photons that may hit the detector, with a full tracking into GEANT4 that simulates their interaction within the central beam pipe.

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TUPVA012

Beam Related Machine Protection of the Future Circular Collider

proton, dipole, operation, beam-losses

2063

Y.C. Nie, M. Jonker, R. Schmidt
CERN, Geneva, Switzerland

In the Future Circular Collider (FCC) study, each nominal proton beam at top particle energy of 50 TeV has an energy of 8500 MJ, which is more than 20 times the energy of today's Large Hadron Collider (LHC) beam. Machine protection of such a high-energy and high-energy density accelerator becomes very challenging. In this paper, preliminary considerations of beam related machine protection issues of the FCC will be reported. Based on the current optics design, a few major critical equipment failures that could potentially lead to very fast (within a few turns) beam losses have been studied. The serious failure scenarios that have been considered, typically occurring at locations with high beta functions, include powering failures of normal conducting magnets, quenches of superconducting magnets as well as critical RF failures. Some fundamental questions related to the beam interlock system, e.g., the need for additional particle free abort gaps to shorten the synchronization time before executing a beam dump, will be discussed.

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TUPVA036

Cross-Talk Studies between FCC-hh Experimental Interaction Regions

detector, proton, simulation, interaction-region

2136

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

Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305.
Debris from 50 TeV proton-proton collisions at the main interaction point in the FCC-hh may contribute to the background in the subsequent detector. This cross-talk is of possible concern for the FCC-hh due to the high luminosity and energy of the collider. DPMJET-III is used as a collision debris generator in order to assess the muon cross-talk contribution. An analytical calculation of muon range in rock is performed. This is followed by a full Monte Carlo simulation using FLUKA, where the accelerator tunnel has been modelled. The muon cross talk between the adjacent interaction points is assessed and its implications for FCC-hh design are discussed.

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TUPVA037

FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies

optics, luminosity, quadrupole, hadron

2139

J.L. Abelleira, E. Cruz Alaniz, A. Seryi, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
M.I. Besana
CERN, Geneva, Switzerland

Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol), EU's Horizon 2020 grant No 654305.
The international Future Circular Collider (FCC) study comprises the study of a new scientific structure in a tunnel of 100 km. This will allow the installation of two accelerators, a 45.6'175 GeV lepton collider and a 100-TeV hadron collider. An optimized design of a final-focus system for the hadron collider is presented here. The new design is more compact and enables unequal β^* in both planes, whose choice is justified here. This is followed by energy deposition studies, where the total dose in the magnets as a consequence of the collision debris is evaluated.

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TUPVA038

Non Linear Field Correction Effects on the Dynamic Aperture of the FCC-hh

quadrupole, lattice, interaction-region, dynamic-aperture

2143

E. Cruz Alaniz, A. Seryi
JAI, Oxford, United Kingdom
E.H. Maclean, R. Martin, R. Tomás
CERN, Geneva, Switzerland

Funding: European Union's Horizon 2020 research and innovation programme under grant No 654305.
The Future Circular Collider (FCC) design study aims to develop the designs of possible circular colliders in the post LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. Given the large beta functions and integrated length of the quadrupoles of the final focus triplet the effect of systematic and random non linear errors in the magnets are expected to have a severe impact on the stability of the beam. Following the experience on the HL-LHC this work explores the implementation of non-linear correctors to minimize the resonance driving terms arising from the errors of the triplet. Dynamic aperture studies are then performed to study the impact of this correction.

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TUPVA039

Effect of Alignment Errors and Orbit Correctors on the Interaction Region of the FCC-hh

quadrupole, interaction-region, optics, dipole

2147

E. Cruz Alaniz, J.L. Abelleira, A. Seryi, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
J.L. Abelleira, L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom

Funding: European Union's Horizon 2020 research and innovation programme under grant No 654305.
The Future Circular Collider (FCC) design study aims to develop the design of possible circular colliders in the LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. The interaction region has been designed to meet the requirements in terms of energy and luminosity. However, as it is the case in any real accelerator, misalignments in the magnets are likely to occur; the effect of these misalignments, if not properly compensated for, can jeopardize the performance of the machine. This study contemplates alignment and field errors in the interaction region in order to estimate the tolerance necessary to provide a good correction measured in terms of deviation of the orbit and strength of the correctors.

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TUPVA043

A Code for Optimising Triplet Layout

quadrupole, shielding, focusing, proton

2163

L. van Riesen-Haupt, J.L. Abelleira, E. Cruz Alaniz, A. Seryi
JAI, Oxford, United Kingdom

Funding: EuroCirCol
One of the main challenges when designing final focus systems of particle accelerators is maximising the beam stay clear in the strong quadrupole magnets of the inner triplet. Moreover it is desirable to keep the quadrupoles in the inner triplet as short as possible for space and costs reasons but also to reduce chromaticity and simplify corrections schemes. An algorithm that explores the triplet parameter space to optimise both these aspects was written. It uses thin lenses as a first approximation for a broad parameter scan and MADX for more precise calculations. The thin lens algorithm is significantly faster than a full scan using MADX and relatively precise at indicating the approximate area where the optimum solution lies.

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TUPVA049

Re-Visiting RHIC Snakes and Spin Orbit

injection, polarization, proton, dipole

2184

F. Méot, R.C. Gupta, H. Huang, A. Marusic, V.H. Ranjbar, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Recent analyses of RHIC run12 to run15 proton-carbon polarimeter measurements have shown significant tilt of the polarization vector from vertical, at high energy essentially. This is confirmed by extensive measurements performed in the present Run 17. Possible origins of such large tilt may reside in snake spin rotation angle or orbit defects, to mention just two. Dedicated simulations have been undertaken to investigate possible causes, they are presented and discussed, they include the computation and use of 3-D field maps of RHIC siberian snakes.

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TUPVA127

Optimisation of the Design of the Future Circular Collider from a Civil Engineering Perspective

civil-engineering, site, lattice, alignment

2392

J.L. Stanyard, V. Mertens, J.A. Osborne
CERN, Geneva, Switzerland
Y. Loo, C. Sturzaker, M. Sykes
ARUP, London, United Kingdom

This paper describes the role of civil engineering in the optimisation of the design of CERN's Future Circular Collider (FCC). The civil engineering team at CERN have employed a bespoke, interactive, geological tool to consider the suitability of multiple layout options for the FCC, situated in the Geneva Basin, in particular quasi-circular options with circumferences in the order of 100 km. The tool has been used to provide feedback on potential lattice designs that are assessed based on criteria such as geological risk, shaft depth and the environmental sensitivities of access and experimental sites. This paper presents the process and some results of the impact of civil engineering on the design of the FCC, in particular on the layout, location, and structural requirements, and also how the optimised design has been used as the basis for a cost and schedule study.

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TUPVA130

CLIC Tuning Performance Under Realistic Error Conditions

luminosity, target, linear-collider, alignment

2403

E. Marín, A. Latina, F. Plassard, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

In this paper we present the latest results regarding the tuning study of the baseline design of the CLIC Final Focus System. In previous studies, 90% of the machines reach 90% of the nominal luminosity, when considering beam position monitor errors and transverse misalignments of magnets for a single beam case. In the present study, roll misalignments and strength errors are also included for both e^- and e⁺ beamlines, making the study a more realistic one. First, second and third order knobs are implemented in the tuning procedure to target the most relevant beam size aberrations. In order to minimise the total number of luminosity measurements a simultaneous scan of various knobs has been developed to cope with the non-fully orthogonality of the knobs. The obtained results for single and double beam studies are presented.

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WEYA1

Crab Cavity Systems for Future Colliders

cavity, luminosity, electron, proton

2474

S. Verdú-Andrés, I. Ben-Zvi, Q. Wu
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
R. Calaga
CERN, Geneva, Switzerland

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, by the US LARP program and by the HL-LHC project.
KEKB was the first facility to implement the crab crossing technique in 2007, for the interaction of electron and positron beams. The High Luminosity Large Hadron Collider (HL-LHC) project envisages the use of crab cavities for increasing and levelling the luminosity of proton-proton collisions in LHC. Crab cavities have also been proposed and studied for future colliders like CLIC, ILC and eRHIC. This contribution will focus on the near and far future of crab cavities for particle colliders.

Slides WEYA1 [6.571 MB]

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WEOBA1

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

collimation, simulation, proton, 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]

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WEOAB3

RF Quadrupole Structures for Transverse Landau Damping in Circular Accelerators

quadrupole, damping, simulation, impedance

2516

M. Schenk, X. Buffat, L.R. Carver, A. Grudiev, K.S.B. Li, E. Métral, K. Papke
CERN, Geneva, Switzerland
A. Maillard
ENS, Paris, France

The beams required for the high luminosity upgrade of the Large Hadron Collider (HL-LHC) and other potential future circular colliders (FCC) call for efficient mechanisms to suppress transverse collective instabilities. In addition to octupole magnets installed for the purpose of Landau damping in the transverse planes, we propose to use radio frequency (rf) quadrupole structures to considerably enhance the aforementioned stabilising effect. By means of the PyHEADTAIL macroparticle tracking code as well as analytical studies, the stabilising mechanism introduced by an rf quadrupole is studied and explained. It is, furthermore, compared to the influence of the second order chromaticity on transverse beam stability.

Slides WEOAB3 [2.537 MB]

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WEPAB124

Study of Hadron-Photon Colliders for Secondary Beam Generation

photon, proton, hadron, secondary-beams

2865

L. Serafini, C. Curatolo
Istituto Nazionale di Fisica Nucleare, Milano, Italy
F. Broggi
INFN/LASA, Segrate (MI), Italy

We summarize the potentialities of combining two well developed technologies, which are advancing the frontiers of hadron colliders and of light sources, namely the hadron colliders for high energy physics, and the FELs for applied and fundamental science with light, towards the generation of secondary beams with unprecedented characteristics. The collision between their typical pulses of high energy protons and X-ray photons opens a collider scenario with potentials for luminosities in excess of 10³⁸ s^-1*cm^-2, adequate to generate TeV-class pion, muon, neutrino and photon beams with very high phase space densities. We report results based on Monte Carlo simulations of such a hadron-photon collider*, aiming at qualifying the features of these secondary beams in view of experiments to be performed directly, or towards the design of a new kind of muon collider.
C. Curatolo, et al., Nuclear Instruments & Methods in Physics Research A (2016), http://dx.doi.org/10.1016/j. nima.2016.09.002i

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WEPAB133

A Wedge Absorber Experiment at MICE

emittance, experiment, optics, scattering

2888

D.V. Neuffer
Fermilab, Batavia, Illinois, USA
T.A. Mohayai
IIT, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA
D.J. Summers
UMiss, University, Mississippi, USA

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

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WEPAB137

Cold Muonium Negative Ion Production

ion, electron, target, plasma

2898

V.G. Dudnikov, M.A. Cummings, R.P. Johnson
Muons, Inc, Illinois, USA
A.V. Dudnikov
BINP SB RAS, Novosibirsk, Russia

Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.

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WEPIK001

Advanced Beam Dump for FCC-ee

simulation, electron, distributed, positron

2906

A. Apyan
ANSL, Yerevan, Armenia
B. Goddard, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.

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WEPIK015

Optimized Monochromatization for Direct Higgs Production in Future Circular e⁺e⁻ Colliders

luminosity, emittance, radiation, electron

2950

F. Zimmermann
CERN, Geneva, Switzerland
M.A. Valdivia García
DCI-UG, León, Mexico

Funding: This work was supported in part by the European Commission under the HORIZON2020 Integrating Activity project ARIES, grant agreement 730871, and by the Mexican CONACyT ‘‘BEAM'' Programme.
Direct s-channel Higgs production in e⁺e⁻ collisions is of interest if the centre-of-mass energy spread can be reduced to be comparable to the width of the standard model Higgs boson. A monochromatization scheme could be employed in order to achieve the desired reduction, by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In high-energy high-luminosity circular colliders, beamstrahlung may increase the energy spread and bunch length. The horizontal emittance blow up due to beamstrahlung, a new effect not present in past monochromatization proposals, may degrade the performance, especially the luminosity. We study, for the FCC-ee at 62.5 GeV beam energy, how we can optimize the IP optics parameters (betax*, Dx*) along with the number of particles per bunch so as to obtain maximum luminosity at a desired target value of the collision energy spread.

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WEPIK016

CEPC-SppC Towards CDR

luminosity, booster, positron, detector

2954

J. Gao
IHEP, Beijing, People's Republic of China

Funding: supported by National Key Programme for S&T Research and Development (2016YFA0400400), National Natural Science Foundation of China (11575218, 11605211, 11605210, 11505198), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH004) and CAS Center for Excellence in Particle Physics (CCEPP)
In this paper we will give an introduction to Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of CEPC are described. On CEPC accelerator, the optimization of parameter designs for CEPC with different energies, machine lengthes, single ring and crab-waist collision partial double ring, advanced partial double partial ring and fully partial double ring options, etc. have been discussed systematically, and compared. CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The sub-systems of CEPC, such as collider main ring, booster, electron positron injector, etc. ave also been introduced. The detector and MDI design have been briefly mentioned. Finally, the optimization design of Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.

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WEPIK017

100 km CEPC Parameters and Lattice Design

luminosity, sextupole, dynamic-aperture, optics

2958

D. Wang, T.J. Bian, X. Cui, J. Gao, H. Geng, Q. Qin, B. Sha, N. Wang, Y. Wang, C.H. Yu, J.Y. Zhai, C. Zhang, Y. Zhang
IHEP, Beijing, People's Republic of China
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

The 100km double ring configuration with shared su-perconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z ex-periment. The luminosity for Z is designed at the level of 1035 cm^-2s⁻¹. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced.

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WEPIK022

CEPC Booster Lattice Design

lattice, resonance, dynamic-aperture, booster

2968

T.J. Bian, X. Cui, J. Gao, C. Zhang
IHEP, Beijing, People's Republic of China

In September 2012, Chinese scientists proposed a Circular Electron Positron Collider(CEPC) at 240 GeV centre of mass for Higgs studies. The CEPC booster(CEPCB) provides 120 GeV electron and positron beams to the CEPC collider for top-up injection. We foucus on the beam dynamic study for CEPCB and analyse the key point of CEPCB lattice design. In this paper, a lattice design with good dynamic aperture is proposed.

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WEPIK026

VEPP-5 Injection Complex: Two Colliders Operation Experience

injection, operation, extraction, positron

2982

D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, M.F. Blinov, D. Bolkhovityanov, A. Butakov, E.V. Bykov, N.S. Dikansky, F.A. Emanov, A.R. Frolov, V.V. Gambaryan, K. Gorchakov, Ye.A. Gusev, S.E. Karnaev, G.V. Karpov, A.S. Kasaev, E. Kenzhebulatov, V.A. Kiselev, S. Kluschev, A.A. Kondakov, I. Koop, I.E. Korenev, N.Kh. Kot, V.R. Kozak, A.A. Krasnov, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, Yu. Maltseva, A.A. Murasev, V. Muslivets, D.A. Nikiforov, An.A. Novikov, A.V. Ottmar, A.V. Pavlenko, I.L. Pivovarov, V.V. Rashchenko, Yu. A. Rogovsky, S.L. Samoylov, N. Sazonov, A.V. Semenov, S.V. Shiyankov, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.S. Vasichev, S.V. Vasiliev, V.D. Yudin, I.M. Zemlyansky, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia
A.V. Andrianov, V.V. Balakin, F.A. Emanov, I. Koop, A.A. Krasnov, A.E. Levichev, D.A. Nikiforov, A.V. Pavlenko, Yu. A. Rogovsky, D.B. Shwartz, A.A. Starostenko
NSU, Novosibirsk, Russia
A.I. Mickailov
Budker INP & NSU, Novosibirsk, Russia
A.G. Tribendis
NSTU, Novosibirsk, Russia

Two BINP colliders VEPP-4M and VEPP-2000 e⁺e⁻ colliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP-4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented.

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WEPIK028

Status of the Electron-Positron Collider VEPP-4

electron, storage-ring, positron, experiment

2985

P.A. Piminov
BINP SB RAS, Novosibirsk, Russia

The next phase of the e⁺e⁻ collider VEPP-4 (Budker INP, Novosibirsk) is focused on experiments in the energy range from 4 to 10 GeV (c.m.). To recover the lack of positrons at high energy a new positron source was connected to the collider. The paper discusses the facility performance with new injection and other aspects of experimental study at high energy including laser polarimeter for precise energy calibration.

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WEPIK029

High Luminosity at VEPP-2000 Collider With New Injector

luminosity, detector, injection, positron

2989

P.Yu. Shatunov, O.V. Belikov, D.E. Berkaev, K. Gorchakov, A.S. Kasaev, A.N. Kirpotin, I. Koop, A.A. Krasnov, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, D.V. Rabusov, Yu. A. Rogovsky, A.M. Semenov, A.I. Senchenko, Y.M. Shatunov, D.B. Shwartz, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia
E. Perevedentsev, Yu. A. Rogovsky, A.I. Senchenko, D.B. Shwartz
NSU, Novosibirsk, Russia

VEPP-2000 e⁺e⁻ collider at BINP was commissioned and started data taking with two detectors in 2010 with old injection chain. In the middle energy range, where the luminosity was limited by beam-beam effects, the world record values of beam-beam parameter were achieved, ksi=0.12/IP. At the same time the design luminosity value of L = 10³² cm^-2s⁻¹ at top energy (E = 1 GeV per beam) remained unreachable due to limited e⁺ production rate. The injection chain was significantly upgraded in 2013-2016. The experience of upgraded VEPP-2000 complex operation at top energies with Round Colliding Beams will be presented.

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WEPIK031

Challenges and Status of the Rapid Cycling Top-Up Booster for FCC-ee

booster, injection, synchrotron, emittance

2996

B. Härer, S. Aumon, B.J. Holzer, Y. Papaphilippou, T. Tydecks
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee is a 100 km e⁺ e⁻ collider, which is being designed within the Future Circular Collider Study (FCC) for precision studies and rare decay observations in the range of 90 to 350 GeV center-of- mass energy. The beam lifetime will be limited to less than one hour, because of radiative Bhaba scattering and beamstrahlung. In order to keep the luminosity on the high level of 10³⁵ cm^-2s^-1 continuous top-up injection is required. Therefore, besides the collider, that will operate at constant energy, a fast cycling booster synchrotron will be installed in the tunnel. The injection energy to the booster synchrotron will be around 6-20 GeV. Such a small energy together with the large bending radius not only creates an ultra-small beam emittance, but also requires very low magnetic fields close to the limit of technical feasibility. This paper will focus on the challenges and requirements for the top-up booster design arising from low magnetic fields and collective instabilities and present the status of the lattice design.

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WEPIK038

Acceleration of Polarized Protons and Deuterons in the Ion Collider Ring of JLEIC

ion, resonance, polarization, proton

3014

V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider's lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of interference peaks. The beam polarization depends on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stabil-ity of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.

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WEPIK081

The Logitudinal Broadband Impedance and Energy Spread Measurements at the VEPP-4M Electron-Positron Collider

impedance, electron, synchrotron, scattering

3117

V.M. Borin, V.A. Kiselev, G.Y. Kurkin, S.A. Nikitin, P.A. Piminov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov, O.I. Meshkov
BINP, Novosibirsk, Russia

The paper presents measurements of the longitudinal broadband impedance and beam energy spread of the beam at the VEPP-4M electron-positron collider in an energy range of 1.0 - 3.5 GeV. In order to measure the longitudinal bunch size at various beam currents we used PS-1/S1 streak camera with picosecond temporal resolution. The dependence of bunch length from the bunch current at different energies demonstrates a microwave instability threshold. The bunch lengthening was caused by potential well distortion as well. Potential well distortion lengthening was used to estimate a value of the reactive part of the longitudinal impedance of the vacuum chamber of the collider Observed microwave instability thresholds was used to measure the value of the broadband impedance. The impact of the Touschek effect in the beam energy spread is discussed.

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WEPIK093

New Methods for Measurement of Nonlinear Errors in LHC Experimental IRs and Their Application in the HL-LHC

dipole, resonance, dynamic-aperture, optics

3155

E.H. Maclean, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, M. Giovannozzi, L. Malina, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

Studies of nonlinear errors in LHC experimental insertions (IRs) during Run 1 were based upon feed-down to tune and coupling from the crossing angle orbit bumps. Useful for validating the magnetic model, this method alone is of limited use to understand discrepancies between magnetic and beam-based measurement. Feed-down from high-order multipoles is also difficult to observe. During Run 2 several alternative methods were tested in the LHC. This paper summarizes the results of these tests, and comments on their potential application to the High-Luminosity LHC upgrade.

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WEPIK114

Study of Electron Polarization Dynamics in the JLEIC at JLab

polarization, electron, simulation, synchrotron

3218

F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The design of an electron polarization scheme in the Jefferson Lab Electron-Ion Collider (JLEIC) aims to attain a high longitudinal electron polarization (over 70%) at collision points as required by the nuclear physics program. Comprehensive strategies for achieving this goal have been considered and developed including injection of highly polarized electrons from CEBAF, mechanisms for manipulation and preservation of the polarization in the JLEIC collider ring and measurement of the electron polarization. In particular, maintaining a sufficiently long polarization lifetime is crucial for accumulation of adequate experimental statistics. The chosen electron polarization configuration, based on the unique figure-8 geometry of the ring, removes the electron spin-tune energy dependence. This significantly simplifies the control of the electron polarization and suppresses the synchrotron sideband resonances. This paper reports recent studies and simulations of the electron polarization dynamics in the JLEIC electron collider ring.

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WEPVA024

Design of an Inductive Adder for the FCC Injection Kicker Pulse Generator

kicker, injection, impedance, high-voltage

3312

D. Woog, M.J. Barnes, L. Ducimetière, J. Holma, T. Kramer
CERN, Geneva, Switzerland

The injection system for a 100 TeV centre-of-mass collider is an important part of the Future Circular Collider (FCC) study. Due to issues with conventional kicker systems, such as self-triggering and long term availability of thyratrons and limitations of HV-cables, innovative design changes are planned for the FCC injection kicker pulse generator. An inductive adder (IA) based on semiconductor (SC) switches is a promising technology for kicker systems. Its modular design, and the possibility of an active ripple suppression are significant advantages. Since the IA is a complex device, with multiple components whose characteristics are important, a detailed design study and construction of a prototype is necessary. This paper summarizes the system requirements and constraints, and describes the main components and design challenges of the prototype IA. It outlines the results from simulations and measurements on different magnetic core materials as well as on SC switches. The paper concludes on the design choices and progress for the prototype to be built at CERN.

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WEPVA071

Preliminary Conceptual Study of Next Generation Tau-Charm Factory at China

luminosity, factory, positron, electron

3436

Q. Luo
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China 11375178 and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046
As BEPC II would accomplish its mission in the next decade, research on high energy science demands a successor. The luminosity of this successor should be one or two orders higher than BEPC II, while the electron beam should be longitudinal polarized at the IP. This paper discusses the feasibility and key technologies of the next tau-charm collider: a greenfield new facility or an upgrade of BEPC II.

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WEPVA087

Magnetic Measurements of NICA Booster Dipoles

dipole, booster, injection, synchrotron

3458

V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin, M.M. Omelyanenko, M.M. Shandov
JINR, Dubna, Moscow Region, Russia
A.V. Shemchuk
JINR/VBLHEP, Dubna, Moscow region, Russia

NICA is a new accelerator collider complex under construction at the Joint Institute for Nuclear Research in Dubna. NICA booster magnetic system consists of 40 dipole and 48 quadrupole superconducting magnets. Measurement of magnetic field parameters is assumed for each booster magnets. At the moment 20 series dipole magnets are assembled and have passed all tests. Booster dipole magnets are 2.14 m-long, 128 /65 mm (h/v) aperture magnets with design similar to Nuclotron dipole magnet but with curved (14.1 m radius) yoke. They will produce fields up to 1.8 T. The magnetic field parameters will be measured at warm (300 K) and cold (4.5 K) conditions. This paper describes magnetic measurements methods and developing of magnetic measurements system. The obtained results of magnetic measurements of 20 magnets are summarized here.

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WEPVA089

Magnetic Measurement System for the NICA Quadrupole Magnets

quadrupole, booster, controls, superconducting-magnet

3464

A.V. Shemchuk
JINR/VBLHEP, Dubna, Moscow region, Russia
V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin, M.M. Omelyanenko, M.M. Shandov
JINR, Dubna, Moscow Region, Russia

NICA is a new accelerator collider Nuclear Research (JINR) in Dubna. More than 250 superconducting magnets need for the NICA booster and collider. These magnets will be assembled and tested at the new test facility in the Laboratory of High Energy Physics JINR. A method of measuring the quality of the magnetic field in the aperture of the quadrupole magnet for the booster synchrotron is described. Commissioning of equipment for magnetic measurements in the aperture of the doublet of quadrupole lenses is described.

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WEPVA095

Preliminary Estimate of Beam Induced Power Deposition in a FCC-hh Injection Kicker Magnet

kicker, impedance, injection, coupling

3475

A. Chmielinska, M.J. Barnes, W. Bartmann, F. Burkart, B. Goddard
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland

The Future Circular Collider for hadrons (FCC-hh) will require a fast injection kicker system that is highly reliable and that does not limit accelerator performance. Important considerations in the design of such a system are machine protection constraints, collider filling factor and hence rise and fall times of the kicker magnet field. Fast rise time kicker magnets are generally ferrite loaded transmission line type magnets with a rectangular shaped aperture. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, beam-induced heating of the ferrite yoke due to the real component of the longitudinal beam coupling impedance needs to be controlled: if the ferrite temperature exceeds the Curie point this impacts the ability to inject beam and hence the availability of the machine. This paper presents estimates for the beam induced power deposition in the ferrite yoke, based on a calculated FCC beam spectrum and an analytical model of longitudinal impedance for unshielded kicker magnets.

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WEPVA098

Measurements on a 12.5 kV Prototype Inductive Adder for the CLIC DR Extraction Kickers

flattop, kicker, extraction, damping

3487

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely stable field pulses during injection and extraction of bunches. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. The current specifications for the modulators call for pulses with 160 ns or 900 ns flattop duration of ±12.5 kV and 305 A, with ripple of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because analogue modulation methods can be applied to adjust the output waveform. Recently, the first full-scale, 20-layer, 12.5 kV prototype inductive adder has been assembled at CERN and testing has commenced. The goal is to tailor the output waveform of the prototype to the waveform required for the DR extraction stripline kicker. The results of the initial tests and measurements are presented.

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WEPVA111

Change of Critical Current Density in Nb-Ti and Nb3Sn Strands After Millisecond Heating

superconducting-magnet, experiment, dipole, luminosity

3528

V. Raginel, K. Kulesz, M. Mentink, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland
D. Kleiven
NTNU, Trondheim, Norway

The damage mechanisms and limits of superconducting magnet components due to direct beam impact are not well understood. The energy deposition from beam losses can cause significant temperature rise and mechanical stress in the magnet coils, which can lead to a degradation of the insulation strength and critical current of the superconductor. An improved understanding of these mechanisms is not only important for the LHC in view of the planned increase in beam brightness, but also for other high energy accelerators using superconducting magnets. An experimental road map has been defined to study these damage mechanisms. Experiments have been performed with Nb-Ti and Nb3Sn strands and cable stacks at room temperature. This contribution focuses on the experimental study on the effect of millisecond heating on superconducting strands.

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WEPVA112

Characterisation of the Mechanical Behaviour of Superconducting Cables Used in High Field Magnets From Room Temperature Down to 77K

dipole, luminosity, cryogenics, superconducting-magnet

3532

O. Sacristan De Frutos, M. Daly, P. Ferracin, C. Fichera, M. Guinchard, T. Mikkola, F. Savary, G. Vallone
CERN, Geneva, Switzerland

A comprehensive knowledge of the mechanical properties of the superconducting cable used in high-field magnets is of paramount importance to study and model the behaviour of the magnet coil from assembly to the operational conditions at cryogenic temperature. The mechanical characterisation of such kind of materials presents practical challenges associated with the heterogeneity of the materials, the geometry, size and quality of the samples that can be produced out of actual cables. These constraints impose the undertaking of such measurements from a nonstandard approach, and hence the development of tailor-made tooling. An extensive characterisation campaign for the determination of the mechanical properties of the superconducting cable at room and cryogenic temperature was launched at CERN in order to determine the most relevant mechanical properties of the superconducting cables used in the MQXF and 11T magnets. This paper describes the design of the tooling developed for this specific application as well as the experimental set-up used for the tests, and discusses the outcomes of the matrix of tests performed.

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WEPVA140

Design Studies and Optimization of High-Field Nb₃Sn Dipole Magnets for a Future Very High Energy pp Collider

dipole, magnet-design, operation, quadrupole

3597

V.V. Kashikhin, I. Novitski, A.V. Zlobin
Fermilab, Batavia, Illinois, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
High filed accelerator magnets with operating fields of 15-16 T based on the Nb3Sn superconductor are being considered for the LHC energy upgrade or a future Very High Energy pp Collider. Magnet design studies are being conducted in the U.S., Europe and Asia to explore the limits of the Nb3Sn accelerator magnet technology while optimizing the magnet design and performance parame-ters, and reducing magnet cost. The first results of these studies performed at Fermilab in the framework of the US-MDP are reported in this paper.

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WEPVA147

Iron-Free Detector System for the Linear Collider with Multiple Return Solenoids

solenoid, detector, linear-collider, emittance

3615

A.A. Mikhailichenko
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We investigate the Iron-free magnetic system for implementation in a detector for future Linear Collider. One peculiarity is in usage of many small-diameter solenoids for the flux return. Machine-detector interface is discussed also.

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THPAB020

Coupling Impedances and Collective Effects for FCC-ee

impedance, vacuum, collective-effects, coupling

3734

E. Belli, M. Migliorati
University of Rome La Sapienza, Rome, Italy
G. Castorina, B. Spataro, M. Zobov
INFN/LNF, Frascati (Roma), Italy
A. Novokhatski
SLAC, Menlo Park, California, USA
S. Persichelli
LBNL, Berkeley, California, USA

A very important issue for the Future Circular Collider (FCC) is represented by collective effects due to the self-induced electromagnetic fields, which, acting back on the beam, could produce dangerous instabilities. In this paper we will focus our work on the FCC electron-positron machine: in particular we will study some important sources of wake fields, their coupling impedances and the impact on the beam dynamics. We will also discuss longitudinal and transverse instability thresholds, both for single bunch and multibunch, and indicate some ways to mitigate such instabilities.

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THPAB046

SixTrack for Cleaning Studies: 2017 Updates

collimation, ion, scattering, coupling

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.

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THPAB080

Estimations of Coherent Instabilities for JLEIC

electron, impedance, ion, proton

3903

R. Li
JLab, Newport News, Virginia, USA

Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177
JLEIC is the medium energy electron-ion collider currently under active design at Jefferson Lab*. The design goals of JLEIC are both high luminosity (1033-1034 cm^-2ses⁻¹) and high polarization (>70%) for the electron and light ion beams, for a wide range of electron and ion beam energies and for a wide spectrum of ion species. The unprecedented luminosity goal for this electron-ion collider sets strong requirements for the understanding and management of potential collective effects in JLEIC. In this paper, we present preliminary estimations of single and coupled bunch coherent instabilities for the electron and proton beams at collision energies for the JLEIC design. Further improvement of the estimations and mitigation methods are discussed.
* MEIC design summary, http://arxiv.org/ftp/arxiv/papers/1504/1504.07961.pdf, (2015).

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THPAB082

The Beam-Beam Effect and Its Consequences for the Modeling of the Jefferson Lab EIC

electron, proton, beam-beam-effects, emittance

3909

E.W. Nissen
JLab, Newport News, Virginia, USA

Funding: Notice: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy
In this work we address the effect of beam jitter on emittance growth as caused by the beam-beam effect on the Jefferson Lab Electron Ion Collider (JLEIC). This proposed collider would collide up to 100 GeV proton beams with up to 10 GeV electron beams. Due to the asymmetric rigidities of the beams and their non-linear lensing action on each other during a collision, collective effects can limit beam storage times. Using simulations we determined that one of JLEIC's synchronization concepts would require a new set of software tools to accurately understand phase space evolution.

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THPAB084

Integration of the Full-Acceptance Detector Into the JLEIC

dynamic-aperture, detector, ion, solenoid

3912

G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y.M. Nosochkov
SLAC, Menlo Park, California, USA
M.-H. Wang
Self Employment, Private address, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
For physics requirements, the JLEIC (Jefferson Lab Electron Ion Collider) has a full-acceptance detector, which brings many new challenges to the beam dynamics integration. For example, asymmetric lattice and beam envelopes at interaction region (IR), forward detection, and large crossing angle with crab dynamics. Also some common problems complicate the picture, like coupling and coherent orbit from detector solenoid, high chromaticity and high multipole sensitivity from low beta-star at interaction point (IP), collision mode with different energy and ion species. Meanwhile, to get a luminosity level of a few 10³³ cm^-2ses⁻¹, small beta-star are necessary at the IP, which also means large beta in the final focus area, chromaticity correction sections, etc. This sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole components of magnets are surveyed to get a standard line. And continuously, multipole magnets as dedicated correctors are studied to provide semi-local corrections of specific multipole components beyond the standard line.

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THPAB086

Long-Term Simulations of Beam-Beam Dynamics on GPUs

GPU, simulation, beam-beam-effects, electron

3918

B. Terzić, C.M. Cotnoir, A.L. Godunov, T. Satogata, M. Stefani
ODU, Norfolk, Virginia, USA
A. Arumugam, R.T. Majeti, D. Ranjan, M. Zubair
ODU CS, Norfolk, Virginia, USA
F. Lin, V.S. Morozov, E.W. Nissen, Y. Roblin, T. Satogata, H. Zhang
JLab, Newport News, Virginia, USA

Funding: Jefferson Lab
Future machines such as the electron-ion colliders (JLEIC), linac-ring machines (eRHIC) or LHeC are particularly sensitive to beam-beam effects. This is the limiting factor for long-term stability and high luminosity reach. The complexity of the non-linear dynamics makes it challenging to perform such simulations which require millions of turns. Until recently, most of the methods used linear approximations and/or tracking for a limited number of turns. We have developed a framework which exploits a massively parallel Graphical Processing Units (GPU) architecture to allow for tracking millions of turns in a sympletic way up to an arbitrary order and colliding them at each turn. The code is called GHOST for GPU-accelerated High-Order Symplectic Tracking. As of now, there is no other code in existence that can accurately model the single-particle non-linear dynamics and the beam-beam effect at the same time for a large enough number of turns required to verify the long-term stability of a collider. Our approach relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for the beam-beam interaction.

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THPIK060

Tuning of an S-Band 10 MeV Traveling-Wave Accelerating Structure with a Non-uniform Section

impedance, network, electron, cavity

4233

J.H. Shao, H.B. Chen, C. Gong, J. Shi, X.W. Wu, S.X. Zheng
TUB, Beijing, People's Republic of China

A tuning method of nonuniform travelling wave structures has been developed based on non-resonant perturbation measurement at Tsinghua University. The filed distribution is normalized with the shunt impedance and attenuation of each cell. Then their internal reflection can be deduced and corrected by cavity deforming. This method has been applied to an S-band 10 MeV travelling wave structure successfully. In this paper, the detailed tuning method and cold test results will be presented.

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THPIK097

High Power Tests of a Prototype X-Band Accelerating Structure for CLIC

vacuum, klystron, linac, electron

4318

R. Zennaro, H. Blumer, M. Bopp, T. Garvey, L. Rivkin
PSI, Villigen PSI, Switzerland
T. Argyropoulos, D. Esperante Pereira
IFIC, Valencia, Spain
N. Catalán Lasheras, A. Grudiev, G. McMonagle, A. Solodko, I. Syratchev, R. Wegner, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland
T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia

Funding: Partially funded by SNF FLARE grant 20FL20₁47463
We present the design, construction and high-power test of an X-band radio-frequency accelerating structure, built as a prototype for the CERN LInear Collider (CLIC) study. X-band structures have been attracting increasing attention in recent years with applications foreseen in the domains of compact free electron lasers, medical accelerators and as diagnostics for ultra-short (femtosecond) electron bunches (when used in deflecting mode). To date, the main motivation for developments in this field has been as accelerating structures for linear colliders such as CLIC. In the context of a CERN/PSI collaboration we have built a prototype structure based on an existing CERN design, but with some modification, and following, as closely as possible, the realization and vacuum brazing techniques employed in the production of the C-band structures for the Swiss Free Electron Laser, SwissFEL. We will present the basic design of the structure and describe the fabrication process. The results of high power conditioning of the structure at CERN on an X-box test stand, to assess conditioning times, accelerating field and measure breakdown rates, will also be presented.

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THPIK105

The ZEPTO Dipole: Zero Power Tuneable Optics for CLIC

dipole, permanent-magnet, target, quadrupole

4338

A.R. Bainbridge, J.A. Clarke, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
M. Modena
CERN, Geneva, Switzerland

Permanent magnet (PM) based systems create a significantly reduced power consumption compared to conventional room temperature electromagnets. STFC and CERN are investigating the feasibility of using tuneable PM systems to reduce high electricity and water-cooling costs; plus the associated large scale infrastructure burden in the proposed CLIC accelerator. This collaboration has previously resulted in the development of two tuneable PM Quadrupole systems. We present here a continuation of this work in the development of a pure PM C-Dipole with a tuning range of over 50%. A prototype has been simulated and constructed using a single 50x40x20 cm block of NdFeB which slides horizontally to provide tuning. We outline the design, construction and measurement of a prototype dipole and discuss its suitability as a replacement for electromagnetic systems. Issues including field homogeneity over a large tuning range and the management of high magnetic forces are addressed.

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THPVA052

Preliminary Design of Magnet Support System for CEPC

booster, dipole, quadrupole, sextupole

4557

H. Wang, H. Qu, J.L. Wang, Z. Wang, N. Zhou
IHEP, Beijing, People's Republic of China

Magnet support system is important for CEPC. For the 100 km design of CEPC, there will be thousands of mag-nets and their supports in both collider and booster. Espe-cially, the booster ring is above the collider in the space, the magnets are hung by the supports. The goals of mag-net supports are simple and flexible structure, minimizing the magnet deformation, good stability, low cost and so on. This paper will describe the preliminary design of magnet support system, the optimization to minimize the magnet deformation and the topology optimization of the frame structure in booster.

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THPVA113

Inverse Problem-Based Magnetic Characterization of Weekly Magnetic Alloys

dipole, background, radiation, luminosity

4722

A. Parrella, M.P. Ramos
IT, Lisboa, Portugal
P. Arpaia, A. Liccardo
Naples University Federico II, Science and Technology Pole, Napoli, Italy
M.C.L. Buzio
CERN, Geneva, Switzerland

Understanding the magnetic properties of materials used in accelerator components is becoming more and more important. For example, in the upcoming LHC upgrade at CERN, the increasing luminosity will boost the radiation dose received by the accelerator magnet's coil and consequently decrease its lifespan. Hence, a radiation shield with relative permeability less than 1.005 is required. The goal of this research is to design and validate a new method for characterizing weekly magnetic materials, suitable to be used in quality control of series production. The proposed method is based on inverse analysis approach coupled with a finite-element model. A material with unknown permeability is inserted in the air gap of a dipole magnet and the consequent perturbations of the dipole background flux density are measured. The magnetic permeability is then identified through gray-box inverse modelling, based on a finite-element approach. The results have been used to predict the magnetic impact of the radiation shield and develop further research on this subject.

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FRYCA1

The Future of High-energy Accelerators

electron, proton, hadron, positron

4856

J. Mnich
DESY, Hamburg, Germany

The physics results from high energy colliders, neutrino experiments and from experiments in space are changing the particle physics landscape. In the last decade several accelerator designs and studies have taken shape and reached a high level of maturity both at the high energy and high intensity frontiers. The talk should review the physics questions facing the HEP community and the strategy to address them in view of the next update of the European Strategy for Particle Physics.

Slides FRYCA1 [9.087 MB]

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