IPAC2018 - List of Keywords (collider)

Paper	Title	Other Keywords	Page
MOPMF001	Bunch Schedules for the FCC-ee Pre-injector	linac, injection, booster, positron	79
	S. Ogur, K. Oide, Y. Papaphilippou, F. Zimmermann CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	The latest design of the Future Circular electron-positron Collider (FCC-ee) foresees a luminosity per interaction point above 2.0·10³⁶/cm²/s for operation at the Z pole. The filling from zero current occurs in collision to profit from the bunch lengthening due to beamstrahlung (so-called bootstrapping). At any time when new e^- and e⁺ buckets or bunchlets are injected into the collider, they will collide instantly. For this reason, we may provide the charge in each injected bunch in a way to pre-compensate for anticipated beam loss, and to reach the target luminosity as soon as possible after the first injection. In this way, we optimise the injection schedules for Z-mode so as to reach the peak luminosity in less than 20 minutes by interleaved injection of the two species at some portion of full bucket charge. Filling from zero the injector should allow accumulating 1.7·10¹¹ particles in one collider bucket within at least 10 injections, assuming a total transmission above 80%. In steady-state operation, the injector chain continually produces and accelerates lower bunch charges so as to maintain nearly constant bunch currents and constant peak luminosity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF001
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MOPMF005	Beam Formation in the Alternative JLEIC Ion Complex	booster, linac, injection, proton	91
	B. Mustapha, J.L. Martinez Marin ANL, Argonne, USA Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy / ONP, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The proposed alternative design approach for the JLab-EIC (JLEIC) ion complex uses a more compact linac and pre-booster, and consolidates the electron storage ring (e-ring) as a large booster for the ions. Following a parameter study* showing the feasibility of this alternative design approach, we have adapted the e-ring lattice by adding RF sections to accelerate ion beams*. In this study, we focus on the beam formation for protons and lead ions from the linac to the pre-booster, then into the e-ring until injection to the ion collider ring. Effects such as space charge, intra-beam scattering and the need for beam cooling will determine the total accumulated charge in each ring and the time required from injection from the injector linac to collision in the collider ring. B. Mustapha et al, Proceedings of NAPAC-2016, October 9-14, Chicago, IL. ** B. Mustapha et al, Proceedings of IPAC-2017, May 14-19, Copenhagen, Denmark.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF005
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MOPMF043	Tuning of CLIC-Final Focus System 3 TeV Baseline Design Under Static and Dynamic Imperfections	luminosity, ISOL, linear-collider, simulation	196
	E. Marín, A. Latina, J. Pfingstner, D. Schulte, R. Tomás CERN, Geneva, Switzerland J. Pfingstner University of Oslo, Oslo, Norway
	In this paper we present the tuning study of the Compact Linear Collider - Final Focus System (CLIC-FFS) 3~TeV baseline design under static and dynamic imperfections for the first time. The motion of the FFS magnets due to ground motion and the impact of active and passive mechanisms envisaged to stabilize both e^- and e⁺ systems are described. It is found that the Pre-isolator required for stabilization of the Final Doublet drives the performance of the collider at the final stages of the tuning process. The obtained tuning performance depending on the stabilization techniques are discussed in detail.
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MOPMF046	Simulation of Hydrodynamic Tunneling Caused by High Energy Proton Beam in Copper through Coupling of FLUKA and Autodyn	target, simulation, proton, coupling	204
	Y.C. Nie, A. Bertarelli, F. Carra, C. Fichera, L.K. Mettler, R. Schmidt, D. Wollmann CERN, Geneva, Switzerland
	For machine protection of high-energy colliders, it is important to assess potential damages caused to accelerator components in case large number of bunches are lost at the same place. The numerical assessment requires an iterative execution of an energy-deposition code and a hydrodynamic code, since the hydrodynamic tunneling effect will likely play an important role in the beam-matter interactions. For proton accelerators at CERN and for the Future Circular Collider (FCC), case studies were performed, coupling FLUKA and BIG2. To compare different hydrocodes and not to rely only on BIG2, FLUKA and a commercial tool, Autodyn, have been used to perform these simulations. This paper reports a benchmarking study against a beam test performed at the HiRadMat (High-Radiation to Materials) facility using beams at 440 GeV from the Super Proton Synchrotron. Good agreement has been found between the simulation results and the test as well as previous simulations with FLUKA and BIG2, particularly in terms of penetration depth of the beam in copper. This makes the coupling of FLUKA and Autodyn an alternative solution to simulating the hydrodynamic tunneling. More case studies are planned for FCC and other high-beam-power accelerators.
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MOPMF056	The Second LHC Long Shutdown (LS2) for the Superconducting Magnets	dipole, hadron, superconducting-magnet, operation	240
	J.Ph. G. L. Tock, M. Bednarek, L. Bottura, E. Karentzos, S.L.N. Le Naour, F. Meuter, M. Pojer, C.E. Scheuerlein, E. Todesco, D. Tommasini, L. X. Van Den Boogaard, G.P. Willering CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) has been delivering data to the physics experiments since 2009. It first operated at a centre of mass energy of 7 TeV and 8 TeV up to the first long shutdown (LS1) in 2013-14. The 13 kA splices between the main LHC cryomagnets were consolidated during LS1. Then, it was possible to increase safely the centre of mass energy to 13 TeV. During the training campaigns, metallic debris caused short circuits in the dipole diode containers, leading to an unacceptable risk. Major interventions can only take place during multiyear shutdowns. To ensure safe operation at higher energies, hence requiring further magnets training, the electrical insulation of the 1232 dipole diodes bus-bars will be consolidated during the second LHC long shutdown (LS2) in 2019-20. The design of the reinforced electrical insulation of the dipole cold diodes and the associated project organisation are presented, including the validation tests, especially at cryogenics temperature. During LS2, maintenance interventions on the LHC cryomagnets will also be performed, following the plan based on a statistical analysis of the electrical faults. It is inscribed in the overall strategy to produce collisions at 14 TeV, the LHC design energy, and to push it further towards 15 TeV. We give a first guess on the impact on the LHC failure rate.
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MOPMF059	Status of the FCC-ee Top-Up Booster Synchrotron	booster, optics, emittance, injection	250
	B. Härer, B.J. Holzer, Y. Papaphilippou, T. Tydecks CERN, Geneva, Switzerland
	This contribution presents the status of the top-up booster synchrotron for the FCC electron-positron collider FCC-ee, which is a 100 km electron-positron collider being designed for precision studies and rare decay observations in the range of 90 to 365 GeV centre-of-mass energy. In order to keep the luminosity at a level of the order of 10³⁵ cm^-2s^-1 continuous top-up injection is required, because of the short beam lifetime of less than one hour. The top-up booster synchrotron will be housed in the same tunnel as the collider rings and will ramp up the beam energy from 20 GeV at injection to the full energy between 45.5 GeV and 182.5 GeV depending on operation mode. The lattice design and two possible optics will be presented. The dynamic aperture was investigated for different sextupole schemes with and without misalignments of the lattice components. In addition, wigglers were installed to decrease the damping time and mitigate intra-beam-scattering.
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MOPMF065	LHC- and FCC-Based Muon Colliders	positron, emittance, target, factory	273
	F. Zimmermann CERN, Geneva, Switzerland
	Funding: Work supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871. In recent years, three schemes for producing low-emittance muon beams have been proposed: (1) e⁺e⁻ annihilation above threshold using a positron storage ring with a thin target [M. Boscolo, P. Raimondi et al.], (2) laser/FEL-Compton back-scattering off high-energy proton beams circulating in the LHC or FCC-hh [L. Serafini et al.], (3) the Gamma factory concept, where partially stripped heavy ions collide with a laser pulse to directly generating muons [W. Krasny]. The Gamma factory would also generate copious amounts of positrons which could in turn be used as source for option (1). On the other hand the top-up booster of the FCC-ee design would be an outstanding e⁺ storage ring, at the right beam energy, around 45 GeV. After rapid acceleration the muons, produced in one of the three ways, could be collided in machines like the SPS, LHC or FCC-hh. Possible collider layouts are suggested.
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MOPMF068	Quantum Excitation due to Classical Beamstrahlung in Circular Colliders	photon, simulation, emittance, radiation	281
	M.A. Valdivia García, D. El Khechen, K. Oide, F. Zimmermann CERN, Geneva, Switzerland
	In the collisions of proposed future circular colliders, like FCC-ee and CEPC, the beamstrahlung regime is classical, i.e. with an "Upsilon parameter" much smaller than 1. In the classical regime, for a constant electromagnetic field a simple relation exists between the average photon energy u and the average squared photon energy u², which is the same as for standard synchrotron radiation in storage rings. This relation breaks down, however, if the electromagnetic field is not constant in time and position, as is the case for a beam-beam collision. We derive an analytical expression for u²/u², considering the case of Gaussian-bunch collisions with crossing angle (and possibly crab waist). We compare our result with the photon energies obtained in beam-beam simulation for FCC-ee at beam energies of 45.6 GeV and 175 GeV, using the two independent codes BBWS and Guineapig. Finally, we re-optimize the FCC-ee parameters of a possible mono-chromatization scheme for direct Higgs production at 125 GeV, derived previously, by applying the refined expression for the rms photon energy.
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MOPMF069	The High Energy LHC Beam-Beam Effects studies	octupole, beam-beam-effects, dynamic-aperture, experiment	285
	T. Pieloni, J. Barranco García, L. Rivkin, C. Tambasco EPFL, Lausanne, Switzerland D. Amorim, S. A. Antipov, X. Buffat, B. Salvant, F. Zimmermann CERN, Geneva, Switzerland
	Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI. We present in this paper the studies of beam-beam effects for the High Energy Large Hadron Collider. We will describe and review the different aspects of beam-beam interactions (i.e. orbit effects, Landau damping, compensation schemes and operational set-up). An operational scenario for the collider will also be given as a result of the study.
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MOPMF072	On the Feasibility of a Pulsed 14 TeV C.M.E. Muon Collider in the LHC Tunnel	luminosity, proton, acceleration, SRF	296
	V.D. Shiltsev, D.V. Neuffer Fermilab, Batavia, Illinois, USA
	We will consider technical feasibility, key machine parameters and major challenges of the recently proposed 14 TeV c.m.e. muon-muon collider in the LHC tunnel.
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MOPMF079	The CEPC lattice design with combined dipole magnet	sextupole, dipole, lattice, dynamic-aperture	315
	D. Wang, S. Bai, F.S. Chen, W. Chou, J. Gao, Y.M. Peng, Y. Wang, M. Yang, C.H. Yu, Y. Zhang IHEP, Beijing, People's Republic of China
	For the lattice of CEPC collider ring, the combined magnet (dipole+sextupole) scheme has been developed to reduce the power consumption of the stand-alone sextu-poles. The power consumption of sextupoles has been decreased by 75% due to 50% reduction of strength. The dynamic aperture for the combined magnet scheme is as good as the original lattice. The magnet design for this kind of combined dipole has been done which provides a good support for this new idea.
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MOPMF084	The Progress of CEPC Positron Source Design	positron, target, linac, electron	319
	C. Meng, X.P. Li, G. Pei, J.R. Zhang IHEP, Beijing, People's Republic of China
	Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory. The injector is composed of 10 GeV linac and 120 GeV booster. The linac of CEPC is a normal conducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV and repetition frequency in 100 Hz. The positron source of CEPC is composed of target, flux concentrator, pre-accelerating section and beam separation system. The detailed design of each section of positron source will be presented and discussed, meanwhile the start-to-end dynamic simulation results will be presented also in this paper.
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MOPMF087	Muon Accumulator Ring Requirements for a Low Emittance Muon Collider from Positrons on Target	target, positron, emittance, interaction-region	330
	M. Boscolo, M. Antonelli, O.R. Blanco-García, S. Guiducci INFN/LNF, Frascati (Roma), Italy F. Collamati INFN-Roma1, Rome, Italy L. Keller SLAC, Menlo Park, California, USA S.M. Liuzzo, P. Raimondi ESRF, Grenoble, France D. Schulte CERN, Geneva, Switzerland
	Very low emittance muon beams can be produced by direct annihilation of about 45~GeV positrons on atomic electrons in a thin target. With such a muon beam source, a mu+mu- collider can be designed in the multi-TeV range at very high luminosities. In this scheme two muon accumulator rings are foreseen to recollect the muon bunches that will be injected in the collider. We present in this paper the first consideration of the muon accumulator rings. Realistic muon beam emittance and energy spread coming from the muon target are described. Constraints on the accumulator ring requirements are derived.
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MOPMK007	An Optimised Triplet for the Final Focus of the FCC-HH with a 40m Final Drift	optics, luminosity, quadrupole, injection	364
	L. van Riesen-Haupt, J.L. Abelleira University of Oxford, Oxford, United Kingdom J.L. Abelleira, E. Cruz Alaniz, A. Seryi JAI, Oxford, United Kingdom
	Funding: Work supported by the Horizon 2020 project EuroCirCol, grant 654305 and by the Science and Technology Facilities Council The sizes of the beta functions in the final focus triplet of a synchrotron collider have a great impact on the chromaticity and dynamic aperture of the machine. These beta functions are proportional to the square of the length of the final drift so it is desirable to keep it as short as possible whilst leaving enough room for the experiment. In the latest design of the FCC-hh this drift was reduced from 45 m to 40 m. In the following an alternative final focus for this new design will be presented. The effects this change has on the interaction region will examined and discussed.
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MOPMK011	VEPP-5 Injection Complex: New Possibilities for BINP Electron-Positron Colliders	positron, electron, injection, gun	371
	Yu. Maltseva, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, D.E. Berkaev, 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. Kenzhbulatov, 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, 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, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.P. 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
	VEPP-5 Injection Complex (IC) is designed to supply BINP RAS colliders with high energy electron and positron beams. Recently constructed K-500 beam transfer line connects IC to both VEPP-4M and VEPP-2000 colliders. IC two collider operation was successfully performed in 2016. Nowadays, research on improvement of IC productivity is carried out, in particular 10.94 MHz RF cavity instead of 700 MHz one was installed and a new electron gun installation is expected to be this summer. Moreover, longitudinal beam profile measurements in IC damping ring using a streak-camera were carried out. Operation experience of IC and results of longitudinal beam profile measurements are reported.
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MOPMK012	Electron Cloud Studies in FCC-ee	electron, simulation, quadrupole, vacuum	374
	E. Belli Sapienza University of Rome, Rome, Italy P. Costa Pinto, G. Rumolo, T.F. Sinkovits, M. Taborelli CERN, Geneva, Switzerland M. Migliorati INFN-Roma1, Rome, Italy
	Electron cloud effects are one of the most critical aspects for the LHC and the future circular colliders. In the frame of the electron-positron collider FCC-ee, an estimation of the electron cloud build up in the machine will be discussed in this paper. A preliminary evaluation of the heat load in the arc components and interaction region magnets will be presented, together with possible mitigation strategies.
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MOPMK016	Calculations of Beam-Beam Effect and Luminosity for Crab Dynamics Simulations in JLEIC	luminosity, simulation, electron, beam-beam-effects	386
	H. Huang, V.S. Morozov, A.V. Sy JLab, Newport News, Virgina, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. Crab crossing is an integral part of the Jefferson Lab Electron-Ion Collider (JLEIC) design to achieve high luminosity while meeting the detection and physics pro-gram requirements. The crab crossing scheme provides a head-on beam-beam collision for beams with a nonzero crossing angle. Simulations of crabbing dynamics currently do not include beam-beam effects. We describe a framework for accurate simulation of beam-beam effects on crabbing dynamics by applying a numerical calculation of the Bassetti-Erskine analytic solution to symplectic particle tracking codes. The numerical calculation is benchmarked against the analytic solution by calculating the luminosity reduction for several colliding beam scenarios. Benchmarking results show good agreement be-tween the numerical calculation and analytic solution, paving the way for implementation of the beam-beam kick to Elegant tracking simulations.
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MOPML002	Status of the JLEIC Ion Collider Ring Design	dynamic-aperture, solenoid, detector, survey	394
	G.H. Wei, F. Lin, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, USA
	Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the US DOE Contract DE-AC02-76SF00515. We present an update on the lattice design and beam dynamics study of the ion collider ring of JLEIC (Jefferson Lab Electron Ion Collider). The collider ring consists of two 261.7 degree arcs connected by two straight sections crossing each other. One of the straights houses an interaction region (IR) and is shaped to make a 50 mrad crossing angle with the electron beam at the interaction point (IP) to meet physics requirements. The forward acceptance requirements downstream of the IP in the ion direction lead to an asymmetric IR lattice design. The detector solenoid effects and the multipole fields of the IR magnets further complicate this picture. In this paper, compensation of the detector solenoid effects is considered together with orbit correction and multipole effects. We also study local compensation of the magnet multipoles using dedicated multipole correctors. And an optimization of the betatron tunes is also presented.
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MOPML006	Multi-Stage Electron Cooling Scheme for JLEIC	emittance, proton, electron, simulation	397
	H. Zhang, S.V. Benson, Y.S. Derbenev, Y. Roblin, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. JLEIC is the future electron ion collider under design at Jefferson Lab, which will provide a luminosity up to 10³⁴ cm^-2s^-1. Electron cooling is essential for JLEIC to overcome the intrabeam scattering effect, reduce the ion beam emittance and thus achieve the high luminosity. The cooling time is approximately in proportion to the square of the energy and the 6D emittance. To avoid the difficulty of cooling the ion beam with large emittance at high energy, a multi-stage cooing scheme was designed for JLEIC. The ion beam was cooled at the low energy to reduce the emittance. Then it was ramped up to the collision energy. During the collision, electron cooling is implemented to maintain the emittance and the luminosity. Simulations for proton beam and lead ion beam at various stages are presented in this paper.
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MOPML007	Analysis of Spin Response Function at Beam Interaction Point in JLEIC	resonance, polarization, proton, sextupole	400
	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: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under con-tracts DE-AC05-06OR23177 and DE-AC02-06CH11357. The spin response function is determined by a collid-er's magnetic lattice and allows one to account for con-tributions of perturbing fields to spin resonance strengths. The depolarizing effect of an incoming beam depends significantly on the response function value at the interaction point (IP). We present an analytic calcula-tion of the response function for protons and deuterons at the IP of Jefferson Lab Electron Ion Collider (JLEIC) over its whole momentum range. We find a good agreement of the analytic calculation with our numerical modeling results obtained using a spin tracking code, Zgoubi.
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MOPML010	Challenges and Status of Tuning Simulations for CLIC Traditional Beam Delivery System	luminosity, linear-collider, simulation, lattice	412
	R.M. Bodenstein, P. Burrows JAI, Oxford, United Kingdom E. Marín CERN, Geneva, Switzerland
	The beam delivery system (BDS) for the 3 TeV version of the Compact Linear Collider (CLIC) has two main design types. One type is referred to as the local scheme, as it is approximately one kilometer shorter and corrects the chromaticity in both planes. The other type is referred to as the traditional scheme, and separates the chromaticity correction of each plane into different areas. The expectation early in the studies was that the traditional scheme would be easier to tune. This work will address the problems experienced in tuning simulations for the traditional BDS and describe the current state of these simulations.
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MOPML013	Progress on Preliminary Conceptual Study of HIEPA, a Super Tau-Charm Factory in China	positron, factory, luminosity, electron	422
	Q. Luo, D.R. Xu 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 the most successful tau-charm factory of the world, BEPC II will celebrate its 10th birthday this year and will finish its historical mission in the next decade. Because of its very important role in high energy phys-ics study, BEPC II will certainly need a successor, a new tau-charm collider. This paper discusses the feasi-bility of a greenfield next generation tau-charm collid-er named HIEPA. The luminosity of this successor is about 5×1034 cm−2s−1 pilot and 1×1035cm^-2s⁻¹ nominal, with the electron beam longitudinally polarized at the IP. The general scheme of the accelerators and the beam parameters are shown. Several key technologies such as beam polarization and beam emittance diag-nostics are also discussed.
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TUXGBD3	Ideas and Concepts for Future Electron Ion Colliders	electron, luminosity, polarization, detector	590
	F.C. Pilat ORNL, Oak Ridge, Tennessee, USA
	Different versions of future electron-ion colliders have been proposed by Brookhaven National Laboratory (BNL) and Thomas Jefferson National Laboratory (JLAB), one based on colliding protons in a ring with electrons from an Energy Recovery Linac (ERL), the other two based on ring-ring colliders. To attain the luminosity goal strong hadron cooling is required, as could be provided with several proposed new cooling schemes. Polarization of both colliding beams is essential. This invited talk will compare the various designs and highlight some of the novel ideas and concepts.
	Slides TUXGBD3 [76.608 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBD3
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TUYGBD2	A Review of DAΦNE Performances During the KLOE-2 Run	luminosity, detector, operation, vacuum	624
	C. Milardi, D. Alesini, S. Bini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, S. Caschera, A. D'Uffizi, A. De Santis, G.O. Delle Monache, D.G.C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, A. Gallo, R. Gargana, A. Ghigo, S. Guiducci, C. Ligi, M. Maestri, A. Michelotti, L. Pellegrino, R. Ricci, U. Rotundo, A. Stecchi, A. Stella, M. Zobov INFN/LNF, Frascati (Roma), Italy
	DAΦNE, the Frascati electron-positron accelerator complex, has almost completed the last and more chanlleging period of operation for the KLOE-2 detector. In this context the performances of the collider, based on the Crab-Waist collision scheme, are reviewed and the limiting factors discussed.
	Slides TUYGBD2 [9.928 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUYGBD2
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TUYGBE3	Recent progress of short pulse dielectric two-beam acceleration	acceleration, linear-collider, experiment, wakefield	640
	J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Two-Beam Acceleration (TBA) is a structure-based wakefield acceleration method with the potential to meet the luminosity and cost requirements of a TeV class linear collider. The Argonne Wakefield Accelerator (AWA) facility is developing a dielectric-based short pulse TBA scheme with the potential to withstand high acceleration gradients and to achieve low fabrication cost. Recently, the dielectric short pulse TBA technology was successfully demonstrated using K-band 26 GHz structures, achieving 55 MW output power from the power extractor and 28 MeV/m gradient in the accelerator. To improve the generated rf power, an X-band 11.7 GHz power extractor has been developed, which obtained 10⁵ MW in the high power test. In addition, a novel dielectric disk accelerator (DDA) is currently under investigation to significantly increase the efficiency of linear colliders based on short pulse TBA. Details of these research will be presented in this paper.
	Slides TUYGBE3 [2.219 MB]
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TUPAF045	Studies for Future Fixed-Target Experiments at the LHC in the Framework of the CERN Physics Beyond Colliders Study	target, experiment, proton, luminosity	798
	S. Redaelli, M. Ferro-Luzzi CERN, Geneva, Switzerland C. Hadjidakis IN2P3-CNRS, Orsay, France
	A study on prospects for Physics Beyond Colliders at CERN was launched in September 2016 to assess the capabilities of the existing accelerators complex. Among several other working groups, this initiative triggered the creation of a working group with the scope of studying a few specific proposals to perform fixed-target physics experiments at the Large Hadron Collider (LHC). This includes for example physics experiments with solid or gaseous internal targets, polarized gas targets, and experiments using bent-crystals for halo splitting from beam core for internal targets. The focus of the working group's activities is on the technical feasibility and on implications to the LHC ring. In this paper, the current status of the studies is presented and future plans are discussed.
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TUPAF058	Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation	extraction, kicker, hardware, septum	850
	E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner CERN, Geneva, Switzerland
	A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.
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TUPAF059	Design and Evaluation of FCC-hh Injection Protection Schemes	injection, kicker, dipole, collimation	854
	E. Renner, M.J. Barnes, W. Bartmann, C. Bracco, R. Bruce, F. Burkart, B. Goddard, A. Lechner, L.S. Stoel, F.M. Velotti, C. Wiesner, D. Woog CERN, Geneva, Switzerland
	The Future Circular Collider (FCC) study considers several injector scenarios for FCC-hh, the proposed 100~TeV centre of mass hadron collider located at CERN. The investigated options include amongst others to use the LHC at 3.3~TeV or a superconducting SPS at 1.3~TeV as a High Energy Booster (HEB). Due to the high energy of the injected proton beam and the short time constant of injection failures, a thorough consideration of potential failure cases is of major importance. Further attention has to be given to the fact that the injection is - as in LHC - located upstream of the side experiments. Failure scenarios are identified for both injector options, appropriate designs of injection protection schemes are proposed and first simulations are conducted to validate the protection efficiency.
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TUPMF024	Validation of the Halbach FFAG Cell of Cornell-BNL Energy Recovery Linac	linac, permanent-magnet, quadrupole, focusing	1304
	F. Méot, S.J. Brooks, D. Trbojevic, N. Tsoupas 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. The optical properties of the Halbach technology based CBETA ERL return FFAG arc cell are investigated, using its 3-D OPERA field map model. This includes paraxial and large amplitude motion, tune path, study of resonances, dynamic acceptance, effects of various defects, 300-cell 10k-particle bunches 6D transmission trials. These investigations, a 2~3 year investment, have validated the Halbach technology in the linear FFAG cell application, from the point of view of the beam dynamics, so supporting its approval as the required technology for CBETA, in December 2016.
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TUPML005	Study of a Dielectric Disk Structure for Short Pulse Two-Beam Acceleration	acceleration, impedance, beam-loading, linear-collider	1539
	J.H. Shao, M.E. Conde, D.S. Doran, J.F. Power ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Argonne Flexible Linear Collider (AFLC), a proposed 3 TeV electron-positron linear collider based on two-beam acceleration (TBA) scheme, applies a short pulse length (∼20 ns) to obtain a high accelerating gradient (267 MV/m) and a compact footprint (∼18 km). The baseline design of the main accelerator section adopts 26 GHz K-band traveling-wave dielectric-loaded accelerators (DLA) with an rf to beam efficiency 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚 of 27%. Recently, an alternative structure which is similar to a metallic disk-loaded one but with dielectric disks, noted as dielectric disk accelerator (DDA), has been investigated and optimized, leading to ∼45% improvement in 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚. To demonstrate the key technologies, an X-band prototype structure has been designed and will be tested at Argonne Wakefield Accelerator (AWA) facility with a 300 MW metallic power extractor. Detailed comparison between K-band DLA and DDA for AFLC main accelerator as well as the preliminary design of the X-band DDA prototype will be presented in this paper.
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TUPML007	Short Pulse High Power RF Generation with an X-Band Dielectric Power Extractor	experiment, simulation, acceleration, linear-collider	1546
	J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Short pulse high power rf generation is one of the key technologies for the Argonne Flexible Linear Collider (AFLC), a proposed 3 TeV electron-positron linear collider based on two-beam acceleration (TBA) scheme. Compared with metallic power extractors, dielectric structures have the potential to achieve lower fabrication cost and to withstand higher gradient. Recently, an X-band dielectric power extractor (a.k.a, DPETS) has been developed at the Argonne Wakefield Accelerator (AWA) facility and achieved 10⁵ MW output power when driven by a high charge 8-bunch train separated by 770 ps. The design, the cold test measurement, the preliminary high power test results, and the structure inspection will be presented in this paper.
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TUPML036	ALEGRO, the Advanced LinEar collider study GROup	plasma, laser, linear-collider, acceleration	1619
	P. Muggli MPI, Muenchen, Germany B. Cros CNRS LPGP Univ Paris Sud, Orsay, France
	We briefly describe activities of ALEGRO, the Advanced LinEar collider study GROup.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML036
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TUPML062	A Wedge Test in MICE	emittance, experiment, beam-cooling, simulation	1680
	T.A. Mohayai IIT, Chicago, Illinois, USA D.V. Neuffer Fermilab, Batavia, Illinois, USA 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 cooling channel could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders. Parameters for this test have been explored in simulation and applied to experimental configurations using a wedge absorber in the MICE beam. A wedge absorber has been constructed and placed in MICE and data has been collected for both direct emittance exchange, where the longitudinal emittance decreases, and reverse emittance exchange, where the transverse emittance decreases. The simulation studies that led to the magnet configurations and beam configurations are presented.
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TUPML065	Phase Space Density Evolution in MICE	emittance, simulation, factory, experiment	1692
	D. Rajaram Illinois Institute of Technology, Chicago, Illinois, USA V. Blackmore Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Funding: STFC, DOE, NSF, INFN, and CHIPP The Muon Ionization Cooling Experiment (MICE) collaboration will demonstrate the feasibility of ionization cooling, the technique proposed to cool the muon beam at a future neutrino factory or muon collider. The muon beam parameters are measured before and after the cooling cell using high precision scintillating-fibre trackers in a solenoidal magnetic field. Position and momentum reconstruction of each muon in MICE allows the development of several alternative figures of merit in addition to emittance. Contraction of the phase-space volume of the sample, or equivalently the increase in phases-pace density at its core, is an unequivocal cooling signature. Single-particle amplitude, defined as a weighted distance to the sample centroid, can be used to probe the change in density in the core of the beam. Alternatively, non-parametric statistics provide reliable methods to estimate the entire phase-space density distribution and reconstruct probability contours. The aforementioned techniques, robust to transmission losses and sample non linearities, are ideal candidates for a cooling measurement in MICE. Preliminary results are presented here. Submitted by the MICE Speakers bureau, to be prepared and presented by a MICE member to be selected in due course
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WEPAF019	Fast Readout Algorithm for Cylindrical Beam Position Monitors Providing Good Accuracy for Particle Bunches with Large Offsets	simulation, FPGA, electron, pick-up	1864
	P. Thieberger, D.M. Gassner, R.L. Hulsart, R.J. Michnoff, T.A. Miller, M.G. Minty, Z. Sorrell BNL, Upton, Long Island, New York, USA A.C. Bartnik Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the US Department of Energy. A simple, analytically correct algorithm is developed for calculating 'pencil' beam coordinates using the signals from an ideal cylindrical beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. Finally, the algorithm is used to study the impact of beam-size upon the precision of BPMs in the non-linear region. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized
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WEPAF066	The New CLIC Main Linac Installation and Alignment Strategy	alignment, target, quadrupole, linac	1979
	H. Mainaud Durand, J. Gayde, J. Jaros, M. Sosin, A. P. Zemanek CERN, Geneva, Switzerland V. Rude ESGT-CNAM, Le Mans, France
	A complete solution has been proposed for the pre-alignment of the CLIC main linac in 2012 for the Conceptual Design Report. Two recent studies provide new perspectives for such a pre-alignment. First in a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale (PACMAN), new solutions to fiducialise and align different types of components within a micrometric accuracy on the same support were proposed and validated, using a stretched wire. Secondly, a 5 degree of freedom adjustment platform with plug-in motors showed a very accurate and efficient way to adjust remotely components. By combining the results of both studies, two scenarios of installation and alignment for the CLIC main linac are proposed, providing micrometric and automatized solutions of micrometric assembly, fiducialisation and alignment in metrological labs or in the tunnel. In this paper, the outcome of the two studies are presented; the two scenarios of installation and alignment are then detailed and discussed.
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WEPAF075	Availability Allocation to Particle Accelerators Subsystems by Complexity Criteria	factory, operation, linear-collider, target	2009
	O. Rey Orozko, A. Apollonio, M. Jonker, J.A. Uythoven CERN, Geneva, Switzerland
	In the early design stages of an accelerator, an effective allocation method is needed to translate an overall accelerator availability goal into availability requirements for its subsystems. During the allocation process, many factors are considered to obtain so-called ‘complexity weights', which are at the basis of the system availability allocation. Some of these factors can be measured quantitatively while other have to be assessed qualitatively. Based on our analysis of factors affecting availability, we list six criteria for complexity resulting in an availability allocation of accelerator subsystems. System experts determine the scales of factors and relationships between subsystems. In this paper, we consider four availability apportionment techniques to allocate complexity weights to subsystems. Finally, we apply this method to the Compact Linear Collider (CLIC) and we propose another application of the complexity weights to the Large Hadron Collider (LHC).
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WEPAL004	The Algorithm Research of DBPM for HEPS	synchrotron, radiation, synchrotron-radiation, injection	2147
	F. Liu, J.S. Cao, Y.Y. Du, S.J. Wei IHEP, People's Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, low-emittance, 1300m scale new generation photon source to be built in China [1]. As a key component, digital beam positon monitor (DBPM) needs to make the beam slow acquisition's resolution up to 0.1um. Because of the high requirements and large expenses, we designed our own DBPM system. In this paper, I will present the algorithm of our BPM. The algorithm is based on Discrete Fourier Transform (DFT) method and tested in BEPCII with using our own designed hardware. The Turn-by-Turn's resolution tested in BEPCII is 0.62um (STD value, 65080 counts, 1.2432MHz), the fast acquisition's resolution is 0.32um (STD value, 65080 counts, 10kHz), the slow acquisition's resolution is 0.18um (STD value, 65080 counts, 10Hz).
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WEPMF014	Fast Track Actively Shielded Nb3Sn IR Quadrupole R&D	quadrupole, site, hadron, coupling	2398
	B. Parker, M. Anerella, J.P. Cozzolino, R.C. Gupta, R.B. Palmer, J. Schmalzle, H. Witte BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The Interaction Region (IR) magnets for future Electron Ion Colliders (EIC), such as eRHIC at BNL, JLEIC at JLab and LHeC at CERN, must satisfy strongly opposing requirements. EIC IR superconducting quadrupole coils must provide strong focusing gradients, leading to large peak fields, for the high momentum hadron beam while permitting the nearby electron beam to pass through a nearly field free region. An actively shielded coil geometry does this using nested, opposite polarity, quadrupoles where the combined external fields cancel while leaving a net gradient inside. In order to fabricate and test this concept in a timely and cost effective manner we propose to reuse the inner coils from an existing high gradient Nb3Sn LARP quadrupole inside a new structure with a new NbTi active shield coil. The main challenge is to design a compact structure for applying prestress to the Nb3Sn coil that fits the restricted space inside the shield coil. We first construct a 15 cm long mechanical model of this structure with coil strain gauges to verify the design concept before proceeding with the full coil. Mechanical modeling results and our preliminary design concept are reported here.
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WEPMF063	Thyratron Replacement*	operation, klystron, high-voltage, linear-collider	2512
	I. Roth, N. Butler, M.P.J. Gaudreau, M.K. Kempkes, R.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Funded under US DOE grant no. DE-SC0011292. Thyratrons are typically used as the switch in high power, short pulse modulators with pulse-forming networks. However, thyratrons have a lifetime of only ten to twenty thousand hours, their reservoir heater voltage needs to be adjusted periodically, and reduced overall demand has led multiple thyratron vendors to slow or cease production. In contrast, solid-state switches have a much longer lifetime, need no maintenance, and are based on widely-available commercial items. Despite these advantages, solid-state devices have not historically seen use, due to limited voltage, current, and risetime. Diversified Technologies, Inc. (DTI) has removed this barrier, having developed, built, and tested a thyratron-replacement switch for SLAC based on an array of series and parallel-connected commercial insulated-gate bipolar transistors (IGBTs). This switch has demonstrated operation at very high voltage and current, meeting the full specifications required by SLAC to completely replace (form-fit-function-interface) the L-4888 thyratron: 48 kV, 6.3 kA, and 1 μs risetime.
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WEPMF077	Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators	kicker, flattop, extraction, damping	2557
	J. Holma, M.J. Barnes, A. Ferrero Colomo 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. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.
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WEPML026	Large-Aperture High-Field Nb3Sn Dipole Magnets	dipole, luminosity, operation, magnet-design	2738
	A.V. Zlobin, V.V. Kashikhin, I. Novitski 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 Large-aperture high-field dipole magnets based on Nb3Sn superconductor are necessary for various accelerator systems of future hadron and muon colliders. In hadron colliders, they are used needed for beam separation before and after interaction points. In a muon collider, they are considered for both the arc and the interaction regions to provide room for internal absorbers protecting magnets from the muon decay products. These magnets can also be used in test facilities to produce a background magnetic field for testing conductor samples or insert coils. High level of magnetic field and large aperture size lead to large Lorentz forces and mechanical strains and stresses which can damage brittle Nb3Sn coils. This paper describes conceptual designs of 120-mm aperture dipoles with magnetic fields up to 15 T based on cos-theta coils. Stress management technique and magnet parameters are also presented and discussed.
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WEPML027	Conceptual Design of a 17 T Nb3Sn Accelerator Dipole Magnet	dipole, magnet-design, luminosity, quadrupole	2742
	A.V. Zlobin, J.R. Carmichael, V.V. Kashikhin, I. Novitski 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 Nb3Sn dipole magnets with a nominal field of 16 T and sufficient operation margins are being considered for the LHC energy upgrade or a future Very High Energy Hadron Collider. Magnet design studies are being performed in the framework of the US Magnet Development Program to explore the limits of the Nb3Sn accelerator magnet technology and feasibility of such magnets, as well as to optimize the magnet design, performance parameters and cost. This paper describes the conceptual design of a 17 T dipole magnet with 60 mm aperture and 4-layer cos-theta coil being developed at Fermilab. The results of magnetic and mechanical analyses, including the non-linear effects in magnetic field and the possible stress management techniques, are also presented and discussed.
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WEPML036	Truncated Cosine Theta Magnet and the Applications	septum, extraction, injection, heavy-ion	2772
	K. Sugita, E.S. Fischer, P.J. Spiller GSI, Darmstadt, Germany
	Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.
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WEPML044	Design of HOM Couplers for Superconducting 400 MHz RF Cavities	HOM, cavity, proton, simulation	2793
	N.F. Petry, M. Busch, K. Kümpel, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany
	The Future Circular Collider (FCC) is one possible future successor of the Large Hadron Collider (LHC). The proton-proton collider center-of-mass collision energy is set to 100 TeV with a beam current of 0.5 A. To reach this goal a stable acceleration is critical and therefore higher order modes (HOM) need to be damped. To avoid a high power level in the HOM dampers, further described as couplers, the loaded Q-factor should be below 1000 for the cavity with mounted HOM couplers. Besides a low Q-factor the R/Q value should also be in the range of 1 Ω or below. Two different types of couplers are used to achieve a high damping. The two types are a narrowband Hook-type HOM coupler and a broadband Probe-type HOM coupler. The recent results of the design of the HOM couplers attached to a superconducting 400 MHz RF cavity will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML044
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WEPML071	Superconducting 16-Pole Wiggler for Beijing Electron-Positron Collider II	wiggler, vacuum, impedance, positron	2853
	M.X. Li, X.J. Bian, F.S. Chen, W. Chen, X.J. Sun, H. Wang, J.L. Wang, N. Wang, M.F. Xu, X.C. Yang IHEP, Beijing, People's Republic of China
	A superconducting 16-pole 2.6T wiggler with period 170mm of The High-Energy Photon Source and the Test Facility Project (HEPS-TF) designed and fabricating in the Institute of High Energy Physics (IHEP) in China is described. This wiggler will be installed in Beijing Electron-Positron Collider II (BEPCII). The main parameters and structure of the wiggler are presented. Besides, some vertical testing results are involved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML071
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WEPML076	The Magnetic Measurement of Enhancer-Dipole Magnet for CEPC	positron, collimation, electron, dipole	2866
	Z. Zhang, H. Wang IHEP, Beijing, People's Republic of China
	The CEPC (Circular Electron Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 Gs. In order to save funds for scientific research, we also consider the injection energy of 6 GeV, the magnetic field of deflection magnet is 32 Gs. At the different current, the magnetic field value of the enhancer-dipole magnet can reach the beam energy range of 6 Gev-120 GeV. In such a requirements of magnetic field, the stability of the magnetic field value, repeatability, magnet magnetism, has become an important data for the design parameters of enhancer-dipole magnet. The magnet is measured with the Hall-Probe measurement facility by IHEP. In this paper, first written the procedure of motor control and collection by Labview software, then hen the excitation curve（repeat the measurement six times）, transverse field distribution（repeat the measurement three times）, and integral field distribution are measured. Based on the results of the analysis of large amounts of data, the stability and repeatability of the enhance-dipole magnet in different magnetic fields has summarized and analyzed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML076
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THYGBD1	FCC: Colliders at the Energy Frontier	luminosity, hadron, cavity, injection	2908
	M. Benedikt, F. Zimmermann CERN, Geneva, Switzerland
	The international Future Circular Collider study, launched in 2014, is finalizing a multi-volume conceptual design report. The FCC develops high-energy circular collider options based on a new 100 km tunnel. Long-term goal is a 100 TeV proton-proton collider (FCC-hh). The study also includes a high-luminosity electron-positron collider (FCC-ee), and it also examines lepton-hadron scenarios (FCC-he). Civil engineering and technical infrastructure studies were carried out. Global programs advance the development of high-field superconducting magnet technology based on Nb3Sn, the optimization of a suitable large superconducting RF system, and schemes for synchrotron radiation handling. In addition, the FCC study includes the design of the HE-LHC, housed in the LHC tunnel, and based on the same high-field magnet technology as the FCC-hh. The FCC study further includes an elaboration of the physics cases, including for heavy-ion collisions, and detector concepts, as well as staging and implementation scenarios. The FCC collaboration has grown to more than 120 institutes from 30 countries around the world. This invited talk summarizes the study achievements and the final designs.
	Slides THYGBD1 [12.503 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD1
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THYGBD3	Beam-beam Studies for Super Proton-Proton Collider	luminosity, resonance, closed-orbit, proton	2918
	L.J. Wang, J.Y. Tang IHEP, Beijing, People's Republic of China K. Ohmi KEK, Ibaraki, Japan
	In China, a two-stage circular collider project, CEPC-SPPC has been proposed. The first stage, CEPC (Circular Electron Positron Collier, a so-called Higgs factory) is focused on the Higgs physics, and the second stage, SPPC (Super Proton-Proton Collider) will be an energy frontier collider and a discovery machine. Luminosity is a key factor for any particle-physics colliders. With the increasing bunch population, beam-beam interaction is increasingly become the limit factor of luminosity improvement. The finite crossing angle scheme is considered firstly. Meanwhile, long-range interaction is another significant source of luminosity degrade. In this report, firstly, we don't consider long-range interactions and study luminosity degrade with crossing angle and without crossing angle for horizontal crossing and horizontal-vertical crossing. Secondly we discuss luminosity decay with long-range interactions for horizontal crossing and horizontal-vertical crossing. Thirdly, we talk about emittance growth and luminosity degradation using resonance analysis for different scenarios. Finally the resulting beam-beam limit will be concluded for SPPC.
	Slides THYGBD3 [1.374 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD3
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THYGBD4	Landau Damping by Electron Lenses	electron, proton, octupole, betatron	2921
	A.V. Burov, Y.I. Alexahin, V.D. Shiltsev, A. Valishev Fermilab, Batavia, Illinois, USA
	Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important to note that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.
	Slides THYGBD4 [4.502 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD4
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THPAF047	Measurements and Impact of Stray Fields on the 380 GeV Design of CLIC	site, emittance, dipole, background	3072
	C.G. Gohil, M.C.L. Buzio, E. Marín, D. Schulte CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom
	Previous studies of the 3 TeV Compact Linear Collider (CLIC) design have shown a sensitivity to external dynamic magnetic fields (stray fields) on the nanoTesla level. In this paper the obtained tolerances for stray fields in the 380 GeV CLIC design are presented. In order to determine potential stray field sources, a measurement sensor has been acquired and used to investigate the magnetic contamination from technical equipment. The collected measurements, as well as details of the sensor, are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF047
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THPAF089	Mode Coupling Theory in Collisions With a Large Crossing Angle	coupling, dipole, synchrotron, positron	3197
	N. Kuroo UTTAC, Tsukuba, Ibaraki, Japan K. Hirosawa, K. Ohmi, D. Zhou KEK, Ibaraki, Japan K. Oide, F. Zimmermann CERN, Geneva, Switzerland
	We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 10³⁶ cm^-2s⁻¹. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.
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THPAK052	Single Bunch Instabilities in FCC-ee	impedance, simulation, electron, vacuum	3336
	E. Belli Sapienza University of Rome, Rome, Italy G. Castorina, M. Migliorati INFN-Roma1, Rome, Italy G. Rumolo CERN, Geneva, Switzerland B. Spataro, M. Zobov INFN/LNF, Frascati (Roma), Italy
	FCC-ee is a high luminosity lepton collider with a centre-of-mass energy from 91 to 365 GeV. Due to the machine parameters and pipe dimensions, collective effects due to electromagnetic fields produced by the interaction of the beam with the vacuum chamber can be one of the main limitations to the machine performance. In this frame, an impedance model is required to analyze these instabilities and to find possible solutions for their mitigation. This paper will present the contributions of specific machine components to the total impedance budget and their effects on the beam stability. Single bunch instability thresholds will be estimated in both transverse and longitudinal planes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK052
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THPAK123	Updates on Collective Effects Estimations for JLEIC	electron, impedance, cavity, luminosity	3533
	R. Li, K. E. Deitrick, T.J. Michalski JLab, Newport News, Virginia, USA
	Funding: This work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. JLEIC is the high luminosity and high polarization electron-ion collider (EIC) currently under active design at Jefferson Lab. It aims at high luminosity (10³³~10³⁴ cm^-2s⁻¹) for a wide range of ion species and center-of-mass energies. This luminosity performance relies sensibly on beam stability with high intensity electron and ion beam operation. The impedance budget analysis and the estimations of the single and multibunch instabilities are currently underway. In this paper, we present the update status of estimations for the longitudinal and transverse coherent instabilities, and identify areas or parameter regimes where special attentions for instability mitigations are required.
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THPAL013	First Serial Magnetic Measurements of the NICA Collider Twin-Aperture Dipoles	dipole, booster, storage-ring, superconducting-magnet	3645
	M.M. Shandov, V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin JINR, Dubna, Russia I.I. Donguzov, M. A. Kashunin, V. A. Mykhailenko, T.A. Parfylo, A.V. Shemchuk, D.A. Zolotykh JINR/VBLHEP, Dubna, Moscow region, Russia
	NICA is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to study properties of hot and dense baryonic matter. Magnetic system of the NICA collider includes 80 twin-aperture dipole and 86 quadrupole superconducting magnets. The collider twin-aperture magnet is 1.94 m long, 120 mm/70 mm (h/v) aperture with window-frame design similar to the Nuclotron magnet. The measurement of the magnetic field parameters is supported to be conducted for both apertures of each collider magnet. This paper describes magnetic measurements methods and the development of the dedicated system for serial dipole magnets of the NICA collider.
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THPAL014	Serial Magnetic Measurements for the NICA Quadruple Magnets of the NICA Booster Synchrotron	quadrupole, booster, cryogenics, superconducting-magnet	3649
	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. Shandov JINR, Dubna, Moscow Region, Russia
	NICA is a new accelerator collider complex under con-struction at JINR, Dubna. More than 250 superconducting magnets are needed for the NICA booster and collider. The NICA Booster magnetic system includes 48 quadrupole superconducting magnets. The rotating coils probe developed for series magnetic measurements of booster quadrupoles doublets, as well as measuring methods are described. Results of magnetic measurements in cryogenic conditions for 12 doublets are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL014
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THPAL037	Nano-engineering of Nb3Sn Thin Films to Improve Wire Performance and Reduce Cost	lattice, electron, coupling, dipole	3720
	S.A. Kahn, M.A. Cummings Muons, Inc, Illinois, USA E.Z. Barzi Fermilab, Batavia, Illinois, USA
	State-of-the-art Nb3Sn wires have plateaued in the performance of the critical current density Jc. Chemical and geometrical optimization of the wire layout have produced Nb3Sn wires with average Jc(4.2K, 16T) ~ 1,300 A/mm2. A future high energy hadron collider that is being considered to follow the LHC would need larger Jc and be cost effective. The approach to improving the performance of Nb3Sn conductor would be to introduce enhanced flux pinning mechanisms with nano-engineering techniques.
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THPAL146	802 MHz ERL Cavity Design and Development	cavity, SRF, electron, hadron	3990
	F. Marhauser, S. Castagnola, W.A. Clemens, J.G. Dail, P. Dhakal, F. Fors, J. Henry, R.A. Rimmer, L. Turlington, R.S. Williams JLab, Newport News, Virginia, USA R. Calaga, K.M. Dr. Schirm, E. Jensen CERN, Geneva, Switzerland
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and CERN Contract NR. KE3080/ATS In the framework of a collaboration between CERN and JLab, an SRF accelerating cavity for energy recovery linacs operating at 802 MHz was developed in the context of the CERN's Large Hadron electron Collider (LHeC) design study. A single-cell and a five-cell cavity from fine grain high RRR niobium were built at JLab to validate the basic RF design in vertical tests. Two copper single-cell cavities were produced in parallel for R&D purposes at CERN. The cavity design has since been adapted as baseline for the main linac cavities in the proposed Powerful Energy Recovery Linac Experiment facility (PERLE) at Orsay. Details concerning the cavity fabrication and test results for the Nb cavities are presented.
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THPMK103	Initial Testing of Techniques for Large Scale Rf Conditioning for the Compact Linear Collider	linac, operation, linear-collider, ECR	4548
	T.G. Lucas, M.J. Boland, P.J. Giansiracusa, R.P. Rassool, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia N. Catalán Lasheras, A. Grudiev, T. Lefèvre, G. McMonagle, I. Syratchev, B.J. Woolley, W. Wuensch, V. del Pozo Romano CERN, Geneva, Switzerland J. Paszkiewicz University of Oxford, Oxford, United Kingdom C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy A. Vnuchenko IFIC, Valencia, Spain R. Zennaro PSI, Villigen PSI, Switzerland
	Nominal operating conditions for the Compact Linear Collider (CLIC) 380 GeV requires 72 MV/m loaded accelerating gradients for a 180 ns flat-top pulse. Achieving this requires extensive RF conditioning which past tests have demonstrated can take several months per structure, when conditioned at the nominal repetition rate of 50 Hz. At CERN there are three individual X-band test stands currently operational, testing up to 6 structures concurrently. For CLIC's 380 GeV design, 28,000 accelerating structures will make up the main linac. For a large scale conditioning programme, it is important to understand the RF conditioning process and to optimise the time taken for conditioning. In this paper, we review recent X-band testing results from CERN's test stands. With these results we investigate how to optimise the conditioning process and demonstrate the feasibility of pre-conditioning the structures at a higher repetition rate before installation into the main linac.
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FRXGBD1	Reliability and Availability of Particle Accelerators: Concepts, Lessons, Strategy	operation, luminosity, beam-losses, kicker	5014
	A. Apollonio, L. Ponce, O. Rey Orozko, R. Schmidt, A.P. Siemko, B. Todd, J.A. Uythoven, A.P. Verweij, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	This paper will present the results and latest status of an extensive effort to analyse and improve the reliability and availability of the LHC. After the introduction of basic concepts and definitions, the paper reviews the performance of the LHC in 2015-2017. A direct comparison of the luminosity production years 2016 and 2017 is presented, with a focus on the main differences in the observed failure modes. Based on the lessons learnt in this time window, expectations for the performance during future LHC runs are discussed. In particular, the thought process for the evaluation of the possible full energy exploitation of the LHC is described, considering relevant factors such as the expected availability loss and the risk associated to magnet training.
	Slides FRXGBD1 [7.090 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD1
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FRXGBD4	Observation of Saw-Tooth Effect Orbit in the VEPP-4 M Collider	electron, positron, experiment, storage-ring	5026
	Leshenok D. Leshenok, E.A. Bekhtenev NSU, Novosibirsk, Russia E.A. Bekhtenev, G.V. Karpov, S.A. Nikitin, O.A. Plotnikova BINP SB RAS, Novosibirsk, Russia
	We study the relative position of the electron and posi-tron closed orbits in the VEPP-4M single storage ring collider in experiments on orbit precision monitoring. A difference in the orbits can affect the accuracy of several fundamental experiments, e.g. precise comparison of the electron and positron spin frequencies (the CPT invari-ance test) [1]. In this case, the spin precession frequencies of particles should be compared within at least 5·10^-9. The distinction of frequencies depends on the features of the radial orbits. Ideally, the difference in the electron and positron orbits is set only by distributed radiation losses of particle energy. The corresponding contribution to the total orbit distortions is called the Saw-Tooth effect orbit. Another example of possible precision experiment at VEPP-4M is search for the light speed anisotropy (LSA). In this case, it is necessary to ensure a stability of the difference in the radial orbits of electrons and positrons at a level of 1μm.
	Slides FRXGBD4 [1.602 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD4
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Paper

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MOPMF001

Bunch Schedules for the FCC-ee Pre-injector

linac, injection, booster, positron

79

S. Ogur, K. Oide, Y. Papaphilippou, F. Zimmermann
CERN, Geneva, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

The latest design of the Future Circular electron-positron Collider (FCC-ee) foresees a luminosity per interaction point above 2.0·10³⁶/cm²/s for operation at the Z pole. The filling from zero current occurs in collision to profit from the bunch lengthening due to beamstrahlung (so-called bootstrapping). At any time when new e^- and e⁺ buckets or bunchlets are injected into the collider, they will collide instantly. For this reason, we may provide the charge in each injected bunch in a way to pre-compensate for anticipated beam loss, and to reach the target luminosity as soon as possible after the first injection. In this way, we optimise the injection schedules for Z-mode so as to reach the peak luminosity in less than 20 minutes by interleaved injection of the two species at some portion of full bucket charge. Filling from zero the injector should allow accumulating 1.7·10¹¹ particles in one collider bucket within at least 10 injections, assuming a total transmission above 80%. In steady-state operation, the injector chain continually produces and accelerates lower bunch charges so as to maintain nearly constant bunch currents and constant peak luminosity.

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MOPMF005

Beam Formation in the Alternative JLEIC Ion Complex

booster, linac, injection, proton

91

B. Mustapha, J.L. Martinez Marin
ANL, Argonne, USA
Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy / ONP, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The proposed alternative design approach for the JLab-EIC (JLEIC) ion complex uses a more compact linac and pre-booster, and consolidates the electron storage ring (e-ring) as a large booster for the ions. Following a parameter study* showing the feasibility of this alternative design approach, we have adapted the e-ring lattice by adding RF sections to accelerate ion beams**. In this study, we focus on the beam formation for protons and lead ions from the linac to the pre-booster, then into the e-ring until injection to the ion collider ring. Effects such as space charge, intra-beam scattering and the need for beam cooling will determine the total accumulated charge in each ring and the time required from injection from the injector linac to collision in the collider ring.
* B. Mustapha et al, Proceedings of NAPAC-2016, October 9-14, Chicago, IL.
** B. Mustapha et al, Proceedings of IPAC-2017, May 14-19, Copenhagen, Denmark.

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MOPMF043

Tuning of CLIC-Final Focus System 3 TeV Baseline Design Under Static and Dynamic Imperfections

luminosity, ISOL, linear-collider, simulation

196

E. Marín, A. Latina, J. Pfingstner, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
J. Pfingstner
University of Oslo, Oslo, Norway

In this paper we present the tuning study of the Compact Linear Collider - Final Focus System (CLIC-FFS) 3~TeV baseline design under static and dynamic imperfections for the first time. The motion of the FFS magnets due to ground motion and the impact of active and passive mechanisms envisaged to stabilize both e^- and e⁺ systems are described. It is found that the Pre-isolator required for stabilization of the Final Doublet drives the performance of the collider at the final stages of the tuning process. The obtained tuning performance depending on the stabilization techniques are discussed in detail.

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MOPMF046

Simulation of Hydrodynamic Tunneling Caused by High Energy Proton Beam in Copper through Coupling of FLUKA and Autodyn

target, simulation, proton, coupling

204

Y.C. Nie, A. Bertarelli, F. Carra, C. Fichera, L.K. Mettler, R. Schmidt, D. Wollmann
CERN, Geneva, Switzerland

For machine protection of high-energy colliders, it is important to assess potential damages caused to accelerator components in case large number of bunches are lost at the same place. The numerical assessment requires an iterative execution of an energy-deposition code and a hydrodynamic code, since the hydrodynamic tunneling effect will likely play an important role in the beam-matter interactions. For proton accelerators at CERN and for the Future Circular Collider (FCC), case studies were performed, coupling FLUKA and BIG2. To compare different hydrocodes and not to rely only on BIG2, FLUKA and a commercial tool, Autodyn, have been used to perform these simulations. This paper reports a benchmarking study against a beam test performed at the HiRadMat (High-Radiation to Materials) facility using beams at 440 GeV from the Super Proton Synchrotron. Good agreement has been found between the simulation results and the test as well as previous simulations with FLUKA and BIG2, particularly in terms of penetration depth of the beam in copper. This makes the coupling of FLUKA and Autodyn an alternative solution to simulating the hydrodynamic tunneling. More case studies are planned for FCC and other high-beam-power accelerators.

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MOPMF056

The Second LHC Long Shutdown (LS2) for the Superconducting Magnets

dipole, hadron, superconducting-magnet, operation

240

J.Ph. G. L. Tock, M. Bednarek, L. Bottura, E. Karentzos, S.L.N. Le Naour, F. Meuter, M. Pojer, C.E. Scheuerlein, E. Todesco, D. Tommasini, L. X. Van Den Boogaard, G.P. Willering
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) has been delivering data to the physics experiments since 2009. It first operated at a centre of mass energy of 7 TeV and 8 TeV up to the first long shutdown (LS1) in 2013-14. The 13 kA splices between the main LHC cryomagnets were consolidated during LS1. Then, it was possible to increase safely the centre of mass energy to 13 TeV. During the training campaigns, metallic debris caused short circuits in the dipole diode containers, leading to an unacceptable risk. Major interventions can only take place during multiyear shutdowns. To ensure safe operation at higher energies, hence requiring further magnets training, the electrical insulation of the 1232 dipole diodes bus-bars will be consolidated during the second LHC long shutdown (LS2) in 2019-20. The design of the reinforced electrical insulation of the dipole cold diodes and the associated project organisation are presented, including the validation tests, especially at cryogenics temperature. During LS2, maintenance interventions on the LHC cryomagnets will also be performed, following the plan based on a statistical analysis of the electrical faults. It is inscribed in the overall strategy to produce collisions at 14 TeV, the LHC design energy, and to push it further towards 15 TeV. We give a first guess on the impact on the LHC failure rate.

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MOPMF059

Status of the FCC-ee Top-Up Booster Synchrotron

booster, optics, emittance, injection

250

B. Härer, B.J. Holzer, Y. Papaphilippou, T. Tydecks
CERN, Geneva, Switzerland

This contribution presents the status of the top-up booster synchrotron for the FCC electron-positron collider FCC-ee, which is a 100 km electron-positron collider being designed for precision studies and rare decay observations in the range of 90 to 365 GeV centre-of-mass energy. In order to keep the luminosity at a level of the order of 10³⁵ cm^-2s^-1 continuous top-up injection is required, because of the short beam lifetime of less than one hour. The top-up booster synchrotron will be housed in the same tunnel as the collider rings and will ramp up the beam energy from 20 GeV at injection to the full energy between 45.5 GeV and 182.5 GeV depending on operation mode. The lattice design and two possible optics will be presented. The dynamic aperture was investigated for different sextupole schemes with and without misalignments of the lattice components. In addition, wigglers were installed to decrease the damping time and mitigate intra-beam-scattering.

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MOPMF065

LHC- and FCC-Based Muon Colliders

positron, emittance, target, factory

273

F. Zimmermann
CERN, Geneva, Switzerland

Funding: Work supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871.
In recent years, three schemes for producing low-emittance muon beams have been proposed: (1) e⁺e⁻ annihilation above threshold using a positron storage ring with a thin target [M. Boscolo, P. Raimondi et al.], (2) laser/FEL-Compton back-scattering off high-energy proton beams circulating in the LHC or FCC-hh [L. Serafini et al.], (3) the Gamma factory concept, where partially stripped heavy ions collide with a laser pulse to directly generating muons [W. Krasny]. The Gamma factory would also generate copious amounts of positrons which could in turn be used as source for option (1). On the other hand the top-up booster of the FCC-ee design would be an outstanding e⁺ storage ring, at the right beam energy, around 45 GeV. After rapid acceleration the muons, produced in one of the three ways, could be collided in machines like the SPS, LHC or FCC-hh. Possible collider layouts are suggested.

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MOPMF068

Quantum Excitation due to Classical Beamstrahlung in Circular Colliders

photon, simulation, emittance, radiation

281

M.A. Valdivia García, D. El Khechen, K. Oide, F. Zimmermann
CERN, Geneva, Switzerland

In the collisions of proposed future circular colliders, like FCC-ee and CEPC, the beamstrahlung regime is classical, i.e. with an "Upsilon parameter" much smaller than 1. In the classical regime, for a constant electromagnetic field a simple relation exists between the average photon energy u and the average squared photon energy u², which is the same as for standard synchrotron radiation in storage rings. This relation breaks down, however, if the electromagnetic field is not constant in time and position, as is the case for a beam-beam collision. We derive an analytical expression for u²/u², considering the case of Gaussian-bunch collisions with crossing angle (and possibly crab waist). We compare our result with the photon energies obtained in beam-beam simulation for FCC-ee at beam energies of 45.6 GeV and 175 GeV, using the two independent codes BBWS and Guineapig. Finally, we re-optimize the FCC-ee parameters of a possible mono-chromatization scheme for direct Higgs production at 125 GeV, derived previously, by applying the refined expression for the rms photon energy.

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MOPMF069

The High Energy LHC Beam-Beam Effects studies

octupole, beam-beam-effects, dynamic-aperture, experiment

285

T. Pieloni, J. Barranco García, L. Rivkin, C. Tambasco
EPFL, Lausanne, Switzerland
D. Amorim, S. A. Antipov, X. Buffat, B. Salvant, F. Zimmermann
CERN, Geneva, Switzerland

Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI.
We present in this paper the studies of beam-beam effects for the High Energy Large Hadron Collider. We will describe and review the different aspects of beam-beam interactions (i.e. orbit effects, Landau damping, compensation schemes and operational set-up). An operational scenario for the collider will also be given as a result of the study.

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MOPMF072

On the Feasibility of a Pulsed 14 TeV C.M.E. Muon Collider in the LHC Tunnel

luminosity, proton, acceleration, SRF

296

V.D. Shiltsev, D.V. Neuffer
Fermilab, Batavia, Illinois, USA

We will consider technical feasibility, key machine parameters and major challenges of the recently proposed 14 TeV c.m.e. muon-muon collider in the LHC tunnel.

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MOPMF079

The CEPC lattice design with combined dipole magnet

sextupole, dipole, lattice, dynamic-aperture

315

D. Wang, S. Bai, F.S. Chen, W. Chou, J. Gao, Y.M. Peng, Y. Wang, M. Yang, C.H. Yu, Y. Zhang
IHEP, Beijing, People's Republic of China

For the lattice of CEPC collider ring, the combined magnet (dipole+sextupole) scheme has been developed to reduce the power consumption of the stand-alone sextu-poles. The power consumption of sextupoles has been decreased by 75% due to 50% reduction of strength. The dynamic aperture for the combined magnet scheme is as good as the original lattice. The magnet design for this kind of combined dipole has been done which provides a good support for this new idea.

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MOPMF084

The Progress of CEPC Positron Source Design

positron, target, linac, electron

319

C. Meng, X.P. Li, G. Pei, J.R. Zhang
IHEP, Beijing, People's Republic of China

Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory. The injector is composed of 10 GeV linac and 120 GeV booster. The linac of CEPC is a normal conducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV and repetition frequency in 100 Hz. The positron source of CEPC is composed of target, flux concentrator, pre-accelerating section and beam separation system. The detailed design of each section of positron source will be presented and discussed, meanwhile the start-to-end dynamic simulation results will be presented also in this paper.

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MOPMF087

Muon Accumulator Ring Requirements for a Low Emittance Muon Collider from Positrons on Target

target, positron, emittance, interaction-region

330

M. Boscolo, M. Antonelli, O.R. Blanco-García, S. Guiducci
INFN/LNF, Frascati (Roma), Italy
F. Collamati
INFN-Roma1, Rome, Italy
L. Keller
SLAC, Menlo Park, California, USA
S.M. Liuzzo, P. Raimondi
ESRF, Grenoble, France
D. Schulte
CERN, Geneva, Switzerland

Very low emittance muon beams can be produced by direct annihilation of about 45~GeV positrons on atomic electrons in a thin target. With such a muon beam source, a mu+mu- collider can be designed in the multi-TeV range at very high luminosities. In this scheme two muon accumulator rings are foreseen to recollect the muon bunches that will be injected in the collider. We present in this paper the first consideration of the muon accumulator rings. Realistic muon beam emittance and energy spread coming from the muon target are described. Constraints on the accumulator ring requirements are derived.

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MOPMK007

An Optimised Triplet for the Final Focus of the FCC-HH with a 40m Final Drift

optics, luminosity, quadrupole, injection

364

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

Funding: Work supported by the Horizon 2020 project EuroCirCol, grant 654305 and by the Science and Technology Facilities Council
The sizes of the beta functions in the final focus triplet of a synchrotron collider have a great impact on the chromaticity and dynamic aperture of the machine. These beta functions are proportional to the square of the length of the final drift so it is desirable to keep it as short as possible whilst leaving enough room for the experiment. In the latest design of the FCC-hh this drift was reduced from 45 m to 40 m. In the following an alternative final focus for this new design will be presented. The effects this change has on the interaction region will examined and discussed.

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MOPMK011

VEPP-5 Injection Complex: New Possibilities for BINP Electron-Positron Colliders

positron, electron, injection, gun

371

Yu. Maltseva, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, D.E. Berkaev, 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. Kenzhbulatov, 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, 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, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.P. 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

VEPP-5 Injection Complex (IC) is designed to supply BINP RAS colliders with high energy electron and positron beams. Recently constructed K-500 beam transfer line connects IC to both VEPP-4M and VEPP-2000 colliders. IC two collider operation was successfully performed in 2016. Nowadays, research on improvement of IC productivity is carried out, in particular 10.94 MHz RF cavity instead of 700 MHz one was installed and a new electron gun installation is expected to be this summer. Moreover, longitudinal beam profile measurements in IC damping ring using a streak-camera were carried out. Operation experience of IC and results of longitudinal beam profile measurements are reported.

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MOPMK012

Electron Cloud Studies in FCC-ee

electron, simulation, quadrupole, vacuum

374

E. Belli
Sapienza University of Rome, Rome, Italy
P. Costa Pinto, G. Rumolo, T.F. Sinkovits, M. Taborelli
CERN, Geneva, Switzerland
M. Migliorati
INFN-Roma1, Rome, Italy

Electron cloud effects are one of the most critical aspects for the LHC and the future circular colliders. In the frame of the electron-positron collider FCC-ee, an estimation of the electron cloud build up in the machine will be discussed in this paper. A preliminary evaluation of the heat load in the arc components and interaction region magnets will be presented, together with possible mitigation strategies.

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MOPMK016

Calculations of Beam-Beam Effect and Luminosity for Crab Dynamics Simulations in JLEIC

luminosity, simulation, electron, beam-beam-effects

386

H. Huang, V.S. Morozov, A.V. Sy
JLab, Newport News, Virgina, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contracts DE-AC05-06OR23177 and DE-AC02-06CH11357.
Crab crossing is an integral part of the Jefferson Lab Electron-Ion Collider (JLEIC) design to achieve high luminosity while meeting the detection and physics pro-gram requirements. The crab crossing scheme provides a head-on beam-beam collision for beams with a nonzero crossing angle. Simulations of crabbing dynamics currently do not include beam-beam effects. We describe a framework for accurate simulation of beam-beam effects on crabbing dynamics by applying a numerical calculation of the Bassetti-Erskine analytic solution to symplectic particle tracking codes. The numerical calculation is benchmarked against the analytic solution by calculating the luminosity reduction for several colliding beam scenarios. Benchmarking results show good agreement be-tween the numerical calculation and analytic solution, paving the way for implementation of the beam-beam kick to Elegant tracking simulations.

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MOPML002

Status of the JLEIC Ion Collider Ring Design

dynamic-aperture, solenoid, detector, survey

394

G.H. Wei, F. Lin, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA

Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the US DOE Contract DE-AC02-76SF00515.
We present an update on the lattice design and beam dynamics study of the ion collider ring of JLEIC (Jefferson Lab Electron Ion Collider). The collider ring consists of two 261.7 degree arcs connected by two straight sections crossing each other. One of the straights houses an interaction region (IR) and is shaped to make a 50 mrad crossing angle with the electron beam at the interaction point (IP) to meet physics requirements. The forward acceptance requirements downstream of the IP in the ion direction lead to an asymmetric IR lattice design. The detector solenoid effects and the multipole fields of the IR magnets further complicate this picture. In this paper, compensation of the detector solenoid effects is considered together with orbit correction and multipole effects. We also study local compensation of the magnet multipoles using dedicated multipole correctors. And an optimization of the betatron tunes is also presented.

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MOPML006

Multi-Stage Electron Cooling Scheme for JLEIC

emittance, proton, electron, simulation

397

H. Zhang, S.V. Benson, Y.S. Derbenev, Y. Roblin, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
JLEIC is the future electron ion collider under design at Jefferson Lab, which will provide a luminosity up to 10³⁴ cm^-2s^-1. Electron cooling is essential for JLEIC to overcome the intrabeam scattering effect, reduce the ion beam emittance and thus achieve the high luminosity. The cooling time is approximately in proportion to the square of the energy and the 6D emittance. To avoid the difficulty of cooling the ion beam with large emittance at high energy, a multi-stage cooing scheme was designed for JLEIC. The ion beam was cooled at the low energy to reduce the emittance. Then it was ramped up to the collision energy. During the collision, electron cooling is implemented to maintain the emittance and the luminosity. Simulations for proton beam and lead ion beam at various stages are presented in this paper.

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MOPML007

Analysis of Spin Response Function at Beam Interaction Point in JLEIC

resonance, polarization, proton, sextupole

400

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: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under con-tracts DE-AC05-06OR23177 and DE-AC02-06CH11357.
The spin response function is determined by a collid-er's magnetic lattice and allows one to account for con-tributions of perturbing fields to spin resonance strengths. The depolarizing effect of an incoming beam depends significantly on the response function value at the interaction point (IP). We present an analytic calcula-tion of the response function for protons and deuterons at the IP of Jefferson Lab Electron Ion Collider (JLEIC) over its whole momentum range. We find a good agreement of the analytic calculation with our numerical modeling results obtained using a spin tracking code, Zgoubi.

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MOPML010

Challenges and Status of Tuning Simulations for CLIC Traditional Beam Delivery System

luminosity, linear-collider, simulation, lattice

412

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

The beam delivery system (BDS) for the 3 TeV version of the Compact Linear Collider (CLIC) has two main design types. One type is referred to as the local scheme, as it is approximately one kilometer shorter and corrects the chromaticity in both planes. The other type is referred to as the traditional scheme, and separates the chromaticity correction of each plane into different areas. The expectation early in the studies was that the traditional scheme would be easier to tune. This work will address the problems experienced in tuning simulations for the traditional BDS and describe the current state of these simulations.

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MOPML013

Progress on Preliminary Conceptual Study of HIEPA, a Super Tau-Charm Factory in China

positron, factory, luminosity, electron

422

Q. Luo, D.R. Xu
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 the most successful tau-charm factory of the world, BEPC II will celebrate its 10th birthday this year and will finish its historical mission in the next decade. Because of its very important role in high energy phys-ics study, BEPC II will certainly need a successor, a new tau-charm collider. This paper discusses the feasi-bility of a greenfield next generation tau-charm collid-er named HIEPA. The luminosity of this successor is about 5×1034 cm−2s−1 pilot and 1×1035cm^-2s⁻¹ nominal, with the electron beam longitudinally polarized at the IP. The general scheme of the accelerators and the beam parameters are shown. Several key technologies such as beam polarization and beam emittance diag-nostics are also discussed.

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TUXGBD3

Ideas and Concepts for Future Electron Ion Colliders

electron, luminosity, polarization, detector

590

F.C. Pilat
ORNL, Oak Ridge, Tennessee, USA

Different versions of future electron-ion colliders have been proposed by Brookhaven National Laboratory (BNL) and Thomas Jefferson National Laboratory (JLAB), one based on colliding protons in a ring with electrons from an Energy Recovery Linac (ERL), the other two based on ring-ring colliders. To attain the luminosity goal strong hadron cooling is required, as could be provided with several proposed new cooling schemes. Polarization of both colliding beams is essential. This invited talk will compare the various designs and highlight some of the novel ideas and concepts.

Slides TUXGBD3 [76.608 MB]

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TUYGBD2

A Review of DAΦNE Performances During the KLOE-2 Run

luminosity, detector, operation, vacuum

624

C. Milardi, D. Alesini, S. Bini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, S. Caschera, A. D'Uffizi, A. De Santis, G.O. Delle Monache, D.G.C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, A. Gallo, R. Gargana, A. Ghigo, S. Guiducci, C. Ligi, M. Maestri, A. Michelotti, L. Pellegrino, R. Ricci, U. Rotundo, A. Stecchi, A. Stella, M. Zobov
INFN/LNF, Frascati (Roma), Italy

DAΦNE, the Frascati electron-positron accelerator complex, has almost completed the last and more chanlleging period of operation for the KLOE-2 detector. In this context the performances of the collider, based on the Crab-Waist collision scheme, are reviewed and the limiting factors discussed.

Slides TUYGBD2 [9.928 MB]

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TUYGBE3

Recent progress of short pulse dielectric two-beam acceleration

acceleration, linear-collider, experiment, wakefield

640

J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Two-Beam Acceleration (TBA) is a structure-based wakefield acceleration method with the potential to meet the luminosity and cost requirements of a TeV class linear collider. The Argonne Wakefield Accelerator (AWA) facility is developing a dielectric-based short pulse TBA scheme with the potential to withstand high acceleration gradients and to achieve low fabrication cost. Recently, the dielectric short pulse TBA technology was successfully demonstrated using K-band 26 GHz structures, achieving 55 MW output power from the power extractor and 28 MeV/m gradient in the accelerator. To improve the generated rf power, an X-band 11.7 GHz power extractor has been developed, which obtained 10⁵ MW in the high power test. In addition, a novel dielectric disk accelerator (DDA) is currently under investigation to significantly increase the efficiency of linear colliders based on short pulse TBA. Details of these research will be presented in this paper.

Slides TUYGBE3 [2.219 MB]

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TUPAF045

Studies for Future Fixed-Target Experiments at the LHC in the Framework of the CERN Physics Beyond Colliders Study

target, experiment, proton, luminosity

798

S. Redaelli, M. Ferro-Luzzi
CERN, Geneva, Switzerland
C. Hadjidakis
IN2P3-CNRS, Orsay, France

A study on prospects for Physics Beyond Colliders at CERN was launched in September 2016 to assess the capabilities of the existing accelerators complex. Among several other working groups, this initiative triggered the creation of a working group with the scope of studying a few specific proposals to perform fixed-target physics experiments at the Large Hadron Collider (LHC). This includes for example physics experiments with solid or gaseous internal targets, polarized gas targets, and experiments using bent-crystals for halo splitting from beam core for internal targets. The focus of the working group's activities is on the technical feasibility and on implications to the LHC ring. In this paper, the current status of the studies is presented and future plans are discussed.

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TUPAF058

Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation

extraction, kicker, hardware, septum

850

E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner
CERN, Geneva, Switzerland

A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.

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TUPAF059

Design and Evaluation of FCC-hh Injection Protection Schemes

injection, kicker, dipole, collimation

854

E. Renner, M.J. Barnes, W. Bartmann, C. Bracco, R. Bruce, F. Burkart, B. Goddard, A. Lechner, L.S. Stoel, F.M. Velotti, C. Wiesner, D. Woog
CERN, Geneva, Switzerland

The Future Circular Collider (FCC) study considers several injector scenarios for FCC-hh, the proposed 100~TeV centre of mass hadron collider located at CERN. The investigated options include amongst others to use the LHC at 3.3~TeV or a superconducting SPS at 1.3~TeV as a High Energy Booster (HEB). Due to the high energy of the injected proton beam and the short time constant of injection failures, a thorough consideration of potential failure cases is of major importance. Further attention has to be given to the fact that the injection is - as in LHC - located upstream of the side experiments. Failure scenarios are identified for both injector options, appropriate designs of injection protection schemes are proposed and first simulations are conducted to validate the protection efficiency.

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TUPMF024

Validation of the Halbach FFAG Cell of Cornell-BNL Energy Recovery Linac

linac, permanent-magnet, quadrupole, focusing

1304

F. Méot, S.J. Brooks, D. Trbojevic, N. Tsoupas
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.
The optical properties of the Halbach technology based CBETA ERL return FFAG arc cell are investigated, using its 3-D OPERA field map model. This includes paraxial and large amplitude motion, tune path, study of resonances, dynamic acceptance, effects of various defects, 300-cell 10k-particle bunches 6D transmission trials. These investigations, a 2~3 year investment, have validated the Halbach technology in the linear FFAG cell application, from the point of view of the beam dynamics, so supporting its approval as the required technology for CBETA, in December 2016.

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TUPML005

Study of a Dielectric Disk Structure for Short Pulse Two-Beam Acceleration

acceleration, impedance, beam-loading, linear-collider

1539

J.H. Shao, M.E. Conde, D.S. Doran, J.F. Power
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Argonne Flexible Linear Collider (AFLC), a proposed 3 TeV electron-positron linear collider based on two-beam acceleration (TBA) scheme, applies a short pulse length (∼20 ns) to obtain a high accelerating gradient (267 MV/m) and a compact footprint (∼18 km). The baseline design of the main accelerator section adopts 26 GHz K-band traveling-wave dielectric-loaded accelerators (DLA) with an rf to beam efficiency 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚 of 27%. Recently, an alternative structure which is similar to a metallic disk-loaded one but with dielectric disks, noted as dielectric disk accelerator (DDA), has been investigated and optimized, leading to ∼45% improvement in 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚. To demonstrate the key technologies, an X-band prototype structure has been designed and will be tested at Argonne Wakefield Accelerator (AWA) facility with a 300 MW metallic power extractor. Detailed comparison between K-band DLA and DDA for AFLC main accelerator as well as the preliminary design of the X-band DDA prototype will be presented in this paper.

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TUPML007

Short Pulse High Power RF Generation with an X-Band Dielectric Power Extractor

experiment, simulation, acceleration, linear-collider

1546

J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Short pulse high power rf generation is one of the key technologies for the Argonne Flexible Linear Collider (AFLC), a proposed 3 TeV electron-positron linear collider based on two-beam acceleration (TBA) scheme. Compared with metallic power extractors, dielectric structures have the potential to achieve lower fabrication cost and to withstand higher gradient. Recently, an X-band dielectric power extractor (a.k.a, DPETS) has been developed at the Argonne Wakefield Accelerator (AWA) facility and achieved 10⁵ MW output power when driven by a high charge 8-bunch train separated by 770 ps. The design, the cold test measurement, the preliminary high power test results, and the structure inspection will be presented in this paper.

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TUPML036

ALEGRO, the Advanced LinEar collider study GROup

plasma, laser, linear-collider, acceleration

1619

P. Muggli
MPI, Muenchen, Germany
B. Cros
CNRS LPGP Univ Paris Sud, Orsay, France

We briefly describe activities of ALEGRO, the Advanced LinEar collider study GROup.

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TUPML062

A Wedge Test in MICE

emittance, experiment, beam-cooling, simulation

1680

T.A. Mohayai
IIT, Chicago, Illinois, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA
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 cooling channel could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders. Parameters for this test have been explored in simulation and applied to experimental configurations using a wedge absorber in the MICE beam. A wedge absorber has been constructed and placed in MICE and data has been collected for both direct emittance exchange, where the longitudinal emittance decreases, and reverse emittance exchange, where the transverse emittance decreases. The simulation studies that led to the magnet configurations and beam configurations are presented.

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TUPML065

Phase Space Density Evolution in MICE

emittance, simulation, factory, experiment

1692

D. Rajaram
Illinois Institute of Technology, Chicago, Illinois, USA
V. Blackmore
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: STFC, DOE, NSF, INFN, and CHIPP
The Muon Ionization Cooling Experiment (MICE) collaboration will demonstrate the feasibility of ionization cooling, the technique proposed to cool the muon beam at a future neutrino factory or muon collider. The muon beam parameters are measured before and after the cooling cell using high precision scintillating-fibre trackers in a solenoidal magnetic field. Position and momentum reconstruction of each muon in MICE allows the development of several alternative figures of merit in addition to emittance. Contraction of the phase-space volume of the sample, or equivalently the increase in phases-pace density at its core, is an unequivocal cooling signature. Single-particle amplitude, defined as a weighted distance to the sample centroid, can be used to probe the change in density in the core of the beam. Alternatively, non-parametric statistics provide reliable methods to estimate the entire phase-space density distribution and reconstruct probability contours. The aforementioned techniques, robust to transmission losses and sample non linearities, are ideal candidates for a cooling measurement in MICE. Preliminary results are presented here*.
*Submitted by the MICE Speakers bureau, to be prepared and presented by a MICE member to be selected in due course

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WEPAF019

Fast Readout Algorithm for Cylindrical Beam Position Monitors Providing Good Accuracy for Particle Bunches with Large Offsets

simulation, FPGA, electron, pick-up

1864

P. Thieberger, D.M. Gassner, R.L. Hulsart, R.J. Michnoff, T.A. Miller, M.G. Minty, Z. Sorrell
BNL, Upton, Long Island, New York, USA
A.C. Bartnik
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the US Department of Energy.
A simple, analytically correct algorithm is developed for calculating 'pencil' beam coordinates using the signals from an ideal cylindrical beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. Finally, the algorithm is used to study the impact of beam-size upon the precision of BPMs in the non-linear region. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized

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WEPAF066

The New CLIC Main Linac Installation and Alignment Strategy

alignment, target, quadrupole, linac

1979

H. Mainaud Durand, J. Gayde, J. Jaros, M. Sosin, A. P. Zemanek
CERN, Geneva, Switzerland
V. Rude
ESGT-CNAM, Le Mans, France

A complete solution has been proposed for the pre-alignment of the CLIC main linac in 2012 for the Conceptual Design Report. Two recent studies provide new perspectives for such a pre-alignment. First in a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale (PACMAN), new solutions to fiducialise and align different types of components within a micrometric accuracy on the same support were proposed and validated, using a stretched wire. Secondly, a 5 degree of freedom adjustment platform with plug-in motors showed a very accurate and efficient way to adjust remotely components. By combining the results of both studies, two scenarios of installation and alignment for the CLIC main linac are proposed, providing micrometric and automatized solutions of micrometric assembly, fiducialisation and alignment in metrological labs or in the tunnel. In this paper, the outcome of the two studies are presented; the two scenarios of installation and alignment are then detailed and discussed.

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WEPAF075

Availability Allocation to Particle Accelerators Subsystems by Complexity Criteria

factory, operation, linear-collider, target

2009

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

In the early design stages of an accelerator, an effective allocation method is needed to translate an overall accelerator availability goal into availability requirements for its subsystems. During the allocation process, many factors are considered to obtain so-called ‘complexity weights', which are at the basis of the system availability allocation. Some of these factors can be measured quantitatively while other have to be assessed qualitatively. Based on our analysis of factors affecting availability, we list six criteria for complexity resulting in an availability allocation of accelerator subsystems. System experts determine the scales of factors and relationships between subsystems. In this paper, we consider four availability apportionment techniques to allocate complexity weights to subsystems. Finally, we apply this method to the Compact Linear Collider (CLIC) and we propose another application of the complexity weights to the Large Hadron Collider (LHC).

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WEPAL004

The Algorithm Research of DBPM for HEPS

synchrotron, radiation, synchrotron-radiation, injection

2147

F. Liu, J.S. Cao, Y.Y. Du, S.J. Wei
IHEP, People's Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, low-emittance, 1300m scale new generation photon source to be built in China [1]. As a key component, digital beam positon monitor (DBPM) needs to make the beam slow acquisition's resolution up to 0.1um. Because of the high requirements and large expenses, we designed our own DBPM system. In this paper, I will present the algorithm of our BPM. The algorithm is based on Discrete Fourier Transform (DFT) method and tested in BEPCII with using our own designed hardware. The Turn-by-Turn's resolution tested in BEPCII is 0.62um (STD value, 65080 counts, 1.2432MHz), the fast acquisition's resolution is 0.32um (STD value, 65080 counts, 10kHz), the slow acquisition's resolution is 0.18um (STD value, 65080 counts, 10Hz).

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WEPMF014

Fast Track Actively Shielded Nb3Sn IR Quadrupole R&D

quadrupole, site, hadron, coupling

2398

B. Parker, M. Anerella, J.P. Cozzolino, R.C. Gupta, R.B. Palmer, J. Schmalzle, H. Witte
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Interaction Region (IR) magnets for future Electron Ion Colliders (EIC), such as eRHIC at BNL, JLEIC at JLab and LHeC at CERN, must satisfy strongly opposing requirements. EIC IR superconducting quadrupole coils must provide strong focusing gradients, leading to large peak fields, for the high momentum hadron beam while permitting the nearby electron beam to pass through a nearly field free region. An actively shielded coil geometry does this using nested, opposite polarity, quadrupoles where the combined external fields cancel while leaving a net gradient inside. In order to fabricate and test this concept in a timely and cost effective manner we propose to reuse the inner coils from an existing high gradient Nb3Sn LARP quadrupole inside a new structure with a new NbTi active shield coil. The main challenge is to design a compact structure for applying prestress to the Nb3Sn coil that fits the restricted space inside the shield coil. We first construct a 15 cm long mechanical model of this structure with coil strain gauges to verify the design concept before proceeding with the full coil. Mechanical modeling results and our preliminary design concept are reported here.

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WEPMF063

Thyratron Replacement*

operation, klystron, high-voltage, linear-collider

2512

I. Roth, N. Butler, M.P.J. Gaudreau, M.K. Kempkes, R.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Funded under US DOE grant no. DE-SC0011292.
Thyratrons are typically used as the switch in high power, short pulse modulators with pulse-forming networks. However, thyratrons have a lifetime of only ten to twenty thousand hours, their reservoir heater voltage needs to be adjusted periodically, and reduced overall demand has led multiple thyratron vendors to slow or cease production. In contrast, solid-state switches have a much longer lifetime, need no maintenance, and are based on widely-available commercial items. Despite these advantages, solid-state devices have not historically seen use, due to limited voltage, current, and risetime. Diversified Technologies, Inc. (DTI) has removed this barrier, having developed, built, and tested a thyratron-replacement switch for SLAC based on an array of series and parallel-connected commercial insulated-gate bipolar transistors (IGBTs). This switch has demonstrated operation at very high voltage and current, meeting the full specifications required by SLAC to completely replace (form-fit-function-interface) the L-4888 thyratron: 48 kV, 6.3 kA, and 1 μs risetime.

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WEPMF077

Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators

kicker, flattop, extraction, damping

2557

J. Holma, M.J. Barnes, A. Ferrero Colomo
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. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.

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WEPML026

Large-Aperture High-Field Nb3Sn Dipole Magnets

dipole, luminosity, operation, magnet-design

2738

A.V. Zlobin, V.V. Kashikhin, I. Novitski
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
Large-aperture high-field dipole magnets based on Nb3Sn superconductor are necessary for various accelerator systems of future hadron and muon colliders. In hadron colliders, they are used needed for beam separation before and after interaction points. In a muon collider, they are considered for both the arc and the interaction regions to provide room for internal absorbers protecting magnets from the muon decay products. These magnets can also be used in test facilities to produce a background magnetic field for testing conductor samples or insert coils. High level of magnetic field and large aperture size lead to large Lorentz forces and mechanical strains and stresses which can damage brittle Nb3Sn coils. This paper describes conceptual designs of 120-mm aperture dipoles with magnetic fields up to 15 T based on cos-theta coils. Stress management technique and magnet parameters are also presented and discussed.

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WEPML027

Conceptual Design of a 17 T Nb3Sn Accelerator Dipole Magnet

dipole, magnet-design, luminosity, quadrupole

2742

A.V. Zlobin, J.R. Carmichael, V.V. Kashikhin, I. Novitski
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
Nb3Sn dipole magnets with a nominal field of 16 T and sufficient operation margins are being considered for the LHC energy upgrade or a future Very High Energy Hadron Collider. Magnet design studies are being performed in the framework of the US Magnet Development Program to explore the limits of the Nb3Sn accelerator magnet technology and feasibility of such magnets, as well as to optimize the magnet design, performance parameters and cost. This paper describes the conceptual design of a 17 T dipole magnet with 60 mm aperture and 4-layer cos-theta coil being developed at Fermilab. The results of magnetic and mechanical analyses, including the non-linear effects in magnetic field and the possible stress management techniques, are also presented and discussed.

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WEPML036

Truncated Cosine Theta Magnet and the Applications

septum, extraction, injection, heavy-ion

2772

K. Sugita, E.S. Fischer, P.J. Spiller
GSI, Darmstadt, Germany

Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.

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WEPML044

Design of HOM Couplers for Superconducting 400 MHz RF Cavities

HOM, cavity, proton, simulation

2793

N.F. Petry, M. Busch, K. Kümpel, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany

The Future Circular Collider (FCC) is one possible future successor of the Large Hadron Collider (LHC). The proton-proton collider center-of-mass collision energy is set to 100 TeV with a beam current of 0.5 A. To reach this goal a stable acceleration is critical and therefore higher order modes (HOM) need to be damped. To avoid a high power level in the HOM dampers, further described as couplers, the loaded Q-factor should be below 1000 for the cavity with mounted HOM couplers. Besides a low Q-factor the R/Q value should also be in the range of 1 Ω or below. Two different types of couplers are used to achieve a high damping. The two types are a narrowband Hook-type HOM coupler and a broadband Probe-type HOM coupler. The recent results of the design of the HOM couplers attached to a superconducting 400 MHz RF cavity will be presented.

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WEPML071

Superconducting 16-Pole Wiggler for Beijing Electron-Positron Collider II

wiggler, vacuum, impedance, positron

2853

M.X. Li, X.J. Bian, F.S. Chen, W. Chen, X.J. Sun, H. Wang, J.L. Wang, N. Wang, M.F. Xu, X.C. Yang
IHEP, Beijing, People's Republic of China

A superconducting 16-pole 2.6T wiggler with period 170mm of The High-Energy Photon Source and the Test Facility Project (HEPS-TF) designed and fabricating in the Institute of High Energy Physics (IHEP) in China is described. This wiggler will be installed in Beijing Electron-Positron Collider II (BEPCII). The main parameters and structure of the wiggler are presented. Besides, some vertical testing results are involved.

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WEPML076

The Magnetic Measurement of Enhancer-Dipole Magnet for CEPC

positron, collimation, electron, dipole

2866

Z. Zhang, H. Wang
IHEP, Beijing, People's Republic of China

The CEPC (Circular Electron Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 Gs. In order to save funds for scientific research, we also consider the injection energy of 6 GeV, the magnetic field of deflection magnet is 32 Gs. At the different current, the magnetic field value of the enhancer-dipole magnet can reach the beam energy range of 6 Gev-120 GeV. In such a requirements of magnetic field, the stability of the magnetic field value, repeatability, magnet magnetism, has become an important data for the design parameters of enhancer-dipole magnet. The magnet is measured with the Hall-Probe measurement facility by IHEP. In this paper, first written the procedure of motor control and collection by Labview software, then hen the excitation curve（repeat the measurement six times）, transverse field distribution（repeat the measurement three times）, and integral field distribution are measured. Based on the results of the analysis of large amounts of data, the stability and repeatability of the enhance-dipole magnet in different magnetic fields has summarized and analyzed.

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THYGBD1

FCC: Colliders at the Energy Frontier

luminosity, hadron, cavity, injection

2908

M. Benedikt, F. Zimmermann
CERN, Geneva, Switzerland

The international Future Circular Collider study, launched in 2014, is finalizing a multi-volume conceptual design report. The FCC develops high-energy circular collider options based on a new 100 km tunnel. Long-term goal is a 100 TeV proton-proton collider (FCC-hh). The study also includes a high-luminosity electron-positron collider (FCC-ee), and it also examines lepton-hadron scenarios (FCC-he). Civil engineering and technical infrastructure studies were carried out. Global programs advance the development of high-field superconducting magnet technology based on Nb3Sn, the optimization of a suitable large superconducting RF system, and schemes for synchrotron radiation handling. In addition, the FCC study includes the design of the HE-LHC, housed in the LHC tunnel, and based on the same high-field magnet technology as the FCC-hh. The FCC study further includes an elaboration of the physics cases, including for heavy-ion collisions, and detector concepts, as well as staging and implementation scenarios. The FCC collaboration has grown to more than 120 institutes from 30 countries around the world. This invited talk summarizes the study achievements and the final designs.

Slides THYGBD1 [12.503 MB]

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THYGBD3

Beam-beam Studies for Super Proton-Proton Collider

luminosity, resonance, closed-orbit, proton

2918

L.J. Wang, J.Y. Tang
IHEP, Beijing, People's Republic of China
K. Ohmi
KEK, Ibaraki, Japan

In China, a two-stage circular collider project, CEPC-SPPC has been proposed. The first stage, CEPC (Circular Electron Positron Collier, a so-called Higgs factory) is focused on the Higgs physics, and the second stage, SPPC (Super Proton-Proton Collider) will be an energy frontier collider and a discovery machine. Luminosity is a key factor for any particle-physics colliders. With the increasing bunch population, beam-beam interaction is increasingly become the limit factor of luminosity improvement. The finite crossing angle scheme is considered firstly. Meanwhile, long-range interaction is another significant source of luminosity degrade. In this report, firstly, we don't consider long-range interactions and study luminosity degrade with crossing angle and without crossing angle for horizontal crossing and horizontal-vertical crossing. Secondly we discuss luminosity decay with long-range interactions for horizontal crossing and horizontal-vertical crossing. Thirdly, we talk about emittance growth and luminosity degradation using resonance analysis for different scenarios. Finally the resulting beam-beam limit will be concluded for SPPC.

Slides THYGBD3 [1.374 MB]

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THYGBD4

Landau Damping by Electron Lenses

electron, proton, octupole, betatron

2921

A.V. Burov, Y.I. Alexahin, V.D. Shiltsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important to note that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.

Slides THYGBD4 [4.502 MB]

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THPAF047

Measurements and Impact of Stray Fields on the 380 GeV Design of CLIC

site, emittance, dipole, background

3072

C.G. Gohil, M.C.L. Buzio, E. Marín, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom

Previous studies of the 3 TeV Compact Linear Collider (CLIC) design have shown a sensitivity to external dynamic magnetic fields (stray fields) on the nanoTesla level. In this paper the obtained tolerances for stray fields in the 380 GeV CLIC design are presented. In order to determine potential stray field sources, a measurement sensor has been acquired and used to investigate the magnetic contamination from technical equipment. The collected measurements, as well as details of the sensor, are discussed.

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THPAF089

Mode Coupling Theory in Collisions With a Large Crossing Angle

coupling, dipole, synchrotron, positron

3197

N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
K. Hirosawa, K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
K. Oide, F. Zimmermann
CERN, Geneva, Switzerland

We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 10³⁶ cm^-2s⁻¹. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.

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THPAK052

Single Bunch Instabilities in FCC-ee

impedance, simulation, electron, vacuum

3336

E. Belli
Sapienza University of Rome, Rome, Italy
G. Castorina, M. Migliorati
INFN-Roma1, Rome, Italy
G. Rumolo
CERN, Geneva, Switzerland
B. Spataro, M. Zobov
INFN/LNF, Frascati (Roma), Italy

FCC-ee is a high luminosity lepton collider with a centre-of-mass energy from 91 to 365 GeV. Due to the machine parameters and pipe dimensions, collective effects due to electromagnetic fields produced by the interaction of the beam with the vacuum chamber can be one of the main limitations to the machine performance. In this frame, an impedance model is required to analyze these instabilities and to find possible solutions for their mitigation. This paper will present the contributions of specific machine components to the total impedance budget and their effects on the beam stability. Single bunch instability thresholds will be estimated in both transverse and longitudinal planes.

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THPAK123

Updates on Collective Effects Estimations for JLEIC

electron, impedance, cavity, luminosity

3533

R. Li, K. E. Deitrick, T.J. Michalski
JLab, Newport News, Virginia, USA

Funding: This work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
JLEIC is the high luminosity and high polarization electron-ion collider (EIC) currently under active design at Jefferson Lab. It aims at high luminosity (10³³~10³⁴ cm^-2s⁻¹) for a wide range of ion species and center-of-mass energies. This luminosity performance relies sensibly on beam stability with high intensity electron and ion beam operation. The impedance budget analysis and the estimations of the single and multibunch instabilities are currently underway. In this paper, we present the update status of estimations for the longitudinal and transverse coherent instabilities, and identify areas or parameter regimes where special attentions for instability mitigations are required.

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THPAL013

First Serial Magnetic Measurements of the NICA Collider Twin-Aperture Dipoles

dipole, booster, storage-ring, superconducting-magnet

3645

M.M. Shandov, V.V. Borisov, A.V. Bychkov, A.M. Donyagin, O. Golubitsky, H.G. Khodzhibagiyan, S.A. Kostromin
JINR, Dubna, Russia
I.I. Donguzov, M. A. Kashunin, V. A. Mykhailenko, T.A. Parfylo, A.V. Shemchuk, D.A. Zolotykh
JINR/VBLHEP, Dubna, Moscow region, Russia

NICA is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to study properties of hot and dense baryonic matter. Magnetic system of the NICA collider includes 80 twin-aperture dipole and 86 quadrupole superconducting magnets. The collider twin-aperture magnet is 1.94 m long, 120 mm/70 mm (h/v) aperture with window-frame design similar to the Nuclotron magnet. The measurement of the magnetic field parameters is supported to be conducted for both apertures of each collider magnet. This paper describes magnetic measurements methods and the development of the dedicated system for serial dipole magnets of the NICA collider.

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THPAL014

Serial Magnetic Measurements for the NICA Quadruple Magnets of the NICA Booster Synchrotron

quadrupole, booster, cryogenics, superconducting-magnet

3649

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. Shandov
JINR, Dubna, Moscow Region, Russia

NICA is a new accelerator collider complex under con-struction at JINR, Dubna. More than 250 superconducting magnets are needed for the NICA booster and collider. The NICA Booster magnetic system includes 48 quadrupole superconducting magnets. The rotating coils probe developed for series magnetic measurements of booster quadrupoles doublets, as well as measuring methods are described. Results of magnetic measurements in cryogenic conditions for 12 doublets are presented and discussed.

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THPAL037

Nano-engineering of Nb3Sn Thin Films to Improve Wire Performance and Reduce Cost

lattice, electron, coupling, dipole

3720

S.A. Kahn, M.A. Cummings
Muons, Inc, Illinois, USA
E.Z. Barzi
Fermilab, Batavia, Illinois, USA

State-of-the-art Nb3Sn wires have plateaued in the performance of the critical current density Jc. Chemical and geometrical optimization of the wire layout have produced Nb3Sn wires with average Jc(4.2K, 16T) ~ 1,300 A/mm2. A future high energy hadron collider that is being considered to follow the LHC would need larger Jc and be cost effective. The approach to improving the performance of Nb3Sn conductor would be to introduce enhanced flux pinning mechanisms with nano-engineering techniques.

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THPAL146

802 MHz ERL Cavity Design and Development

cavity, SRF, electron, hadron

3990

F. Marhauser, S. Castagnola, W.A. Clemens, J.G. Dail, P. Dhakal, F. Fors, J. Henry, R.A. Rimmer, L. Turlington, R.S. Williams
JLab, Newport News, Virginia, USA
R. Calaga, K.M. Dr. Schirm, E. Jensen
CERN, Geneva, Switzerland

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and CERN Contract NR. KE3080/ATS
In the framework of a collaboration between CERN and JLab, an SRF accelerating cavity for energy recovery linacs operating at 802 MHz was developed in the context of the CERN's Large Hadron electron Collider (LHeC) design study. A single-cell and a five-cell cavity from fine grain high RRR niobium were built at JLab to validate the basic RF design in vertical tests. Two copper single-cell cavities were produced in parallel for R&D purposes at CERN. The cavity design has since been adapted as baseline for the main linac cavities in the proposed Powerful Energy Recovery Linac Experiment facility (PERLE) at Orsay. Details concerning the cavity fabrication and test results for the Nb cavities are presented.

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THPMK103

Initial Testing of Techniques for Large Scale Rf Conditioning for the Compact Linear Collider

linac, operation, linear-collider, ECR

4548

T.G. Lucas, M.J. Boland, P.J. Giansiracusa, R.P. Rassool, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
N. Catalán Lasheras, A. Grudiev, T. Lefèvre, G. McMonagle, I. Syratchev, B.J. Woolley, W. Wuensch, V. del Pozo Romano
CERN, Geneva, Switzerland
J. Paszkiewicz
University of Oxford, Oxford, United Kingdom
C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Vnuchenko
IFIC, Valencia, Spain
R. Zennaro
PSI, Villigen PSI, Switzerland

Nominal operating conditions for the Compact Linear Collider (CLIC) 380 GeV requires 72 MV/m loaded accelerating gradients for a 180 ns flat-top pulse. Achieving this requires extensive RF conditioning which past tests have demonstrated can take several months per structure, when conditioned at the nominal repetition rate of 50 Hz. At CERN there are three individual X-band test stands currently operational, testing up to 6 structures concurrently. For CLIC's 380 GeV design, 28,000 accelerating structures will make up the main linac. For a large scale conditioning programme, it is important to understand the RF conditioning process and to optimise the time taken for conditioning. In this paper, we review recent X-band testing results from CERN's test stands. With these results we investigate how to optimise the conditioning process and demonstrate the feasibility of pre-conditioning the structures at a higher repetition rate before installation into the main linac.

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FRXGBD1

Reliability and Availability of Particle Accelerators: Concepts, Lessons, Strategy

operation, luminosity, beam-losses, kicker

5014

A. Apollonio, L. Ponce, O. Rey Orozko, R. Schmidt, A.P. Siemko, B. Todd, J.A. Uythoven, A.P. Verweij, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

This paper will present the results and latest status of an extensive effort to analyse and improve the reliability and availability of the LHC. After the introduction of basic concepts and definitions, the paper reviews the performance of the LHC in 2015-2017. A direct comparison of the luminosity production years 2016 and 2017 is presented, with a focus on the main differences in the observed failure modes. Based on the lessons learnt in this time window, expectations for the performance during future LHC runs are discussed. In particular, the thought process for the evaluation of the possible full energy exploitation of the LHC is described, considering relevant factors such as the expected availability loss and the risk associated to magnet training.

Slides FRXGBD1 [7.090 MB]

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FRXGBD4

Observation of Saw-Tooth Effect Orbit in the VEPP-4 M Collider

electron, positron, experiment, storage-ring

5026

Leshenok D. Leshenok, E.A. Bekhtenev
NSU, Novosibirsk, Russia
E.A. Bekhtenev, G.V. Karpov, S.A. Nikitin, O.A. Plotnikova
BINP SB RAS, Novosibirsk, Russia

We study the relative position of the electron and posi-tron closed orbits in the VEPP-4M single storage ring collider in experiments on orbit precision monitoring. A difference in the orbits can affect the accuracy of several fundamental experiments, e.g. precise comparison of the electron and positron spin frequencies (the CPT invari-ance test) [1]. In this case, the spin precession frequencies of particles should be compared within at least 5·10^-9. The distinction of frequencies depends on the features of the radial orbits. Ideally, the difference in the electron and positron orbits is set only by distributed radiation losses of particle energy. The corresponding contribution to the total orbit distortions is called the Saw-Tooth effect orbit. Another example of possible precision experiment at VEPP-4M is search for the light speed anisotropy (LSA). In this case, it is necessary to ensure a stability of the difference in the radial orbits of electrons and positrons at a level of 1μm.

Slides FRXGBD4 [1.602 MB]

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