IPAC2019 - List of Authors (Zimmermann, F.)

Paper	Title	Page
MOPGW019	Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee	112
	D. El Khechen, K. Oide, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW019
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP002	Linac and Damping Ring Designs for the FCC-ee	420
	S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia I. Chaikovska, R. Chehab LAL, Orsay, France K. Furukawa, N. Iida, T. Kamitani, F. Miyahara, K. Oide KEK, Ibaraki, Japan E.V. Ozcan Bogazici University, Bebek / Istanbul, Turkey S.M. Polozov MEPhI, Moscow, Russia L. Rinolfi ESI, Archamps, France F. Yaman IZTECH, Izmir, Turkey
	We report the design of the pre-injector chain for the Future Circular e⁺ e⁻ Collider (FCC-ee) system. The electron beam from a low-emittance RF gun is accelerated by an S-band linac up to 6 GeV. A damping ring at 1.54 GeV is required for emittance cooling of the positron beam. The intermediate energy step from the exit of the S-band linac at 6 GeV to the 20 GeV injection energy of the top-up booster can be provided by the modified Super Proton Synchrotron (SPS), serving as a pre-booster ring (PBR). An alternative option to reach 20 GeV energy would be to extend the S-band linac with a C- or X-band linac. An overall cost optimisation will determine the choice of the final configuration. Beam loss and emittance dilution in the linac due to space charge effects, wakefields, and misalignment of accelerator components can be mitigated by RF phasing and orbit steering. Start-to-end simulations examine the beam transport through the linac up to either 6 GeV or 20 GeV. The results indicate large design margins. Simulations of the beam dynamics in the damping ring (DR) demonstrate a sufficiently large momentum acceptance. Effects of intrabeam scattering and electron cloud instability in the DR are also studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP002
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPMP003	Positron Source for FCC-ee	424
	I. Chaikovska, R. Chehab, A. Faus-Golfe, Y. Han LAL, Orsay, France A. Apyan ANSL, Yerevan, Armenia Y. Enomoto, K. Furukawa, T. Kamitani, F. Miyahara, M. Satoh, Y. Seimiya, T. Suwada KEK, Ibaraki, Japan P.V. Martyshkin BINP SB RAS, Novosibirsk, Russia S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, P. Sievers, F. Zimmermann CERN, Meyrin, Switzerland
	The FCC-ee is a high-luminosity, high-precision circular collider to be constructed in a new 100 km tunnel in the Geneva area. The physics case is well established and the FCC-ee operation is foreseen at 91 GeV (Z-pole), 160 GeV (W pair production threshold), 240 GeV (Higgs resonance) and 365 GeV (t-tbar threshold). Due to the large 6D production emittance and important thermal load in the production target, the positron injector, in particular the positron source, is one of the key elements of the FCC-ee, requiring special attention. To ensure high reliability of the positron source, conventional and hybrid targets are currently under study. The final choice of the positron target will be made based on the estimated performances. In this framework, we present a preliminary design of the FCC-ee positron source, with detailed simulation studies of positron production, capture and primary acceleration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP003
About •	paper received ※ 03 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP023	Dynamic Aperture at Injection Energy for the HE-LHC	480
SUSPFO101	use link to see paper's listing under its alternate paper code
	M. Hofer, M. Giovannozzi, J. Keintzel, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland L. van Riesen-Haupt JAI, Oxford, United Kingdom
	As part of the Future Circular Collider study, the High Energy LHC (HE-LHC) is a proposed hadron collider situated in the already existing LHC tunnel. It aims at achieving a center of mass energy of 27 TeV, almost doubling the design c.o.m. energy of the LHC. This increase in energy relies on the use of 16 T Nb₃Sn dipoles to be developed for the FCC-hh. The field quality of these dipoles is expected to have a big impact on the Dynamic Aperture (DA) at injection energy and subsequently tracking studies are conducted to evaluate the impact of magnetic field errors on the beam dynamics. In the following the results of these studies for the different injection energies considered for the HE-LHC are presented and a possible strategy for increasing the DA are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP023
About •	paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP026	HE-LHC Optics Design Options	492
SUSPFO103	use link to see paper's listing under its alternate paper code
	J. Keintzel, M.P. Crouch, M. Hofer, T. Risselada, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland M. Hofer, J. Keintzel TU Vienna, Wien, Austria L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom L. van Riesen-Haupt JAI, Oxford, United Kingdom
	The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP026
About •	paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPMP035	Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider	516
	M.A. Valdivia García, F. Zimmermann CERN, Meyrin, Switzerland
	Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035
About •	paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPMP037	Updated High-Energy LHC Design	524
	F. Zimmermann, D. Amorim, S.A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, J. Keintzel, R. Kersevan, V. Mertens, J. Molson, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann CERN, Geneva, Switzerland J.L. Abelleira, A. Abramov, E. Cruz Alaniz, H. Pikhartova, A. Seryi, L. van Riesen-Haupt JAI, Oxford, United Kingdom A. Apyan ANSL, Yerevan, Armenia J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco EPFL, Lausanne, Switzerland F. Burkart DESY, Hamburg, Germany Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, USA G. Guillermo Cantón CINVESTAV, Mérida, Mexico K. Ohmi, K. Oide, D. Zhou KEK, Ibaraki, Japan
	Funding: This work was supported in part by the European Commission under the HORIZON 2020 project ARIES no.730871, and by the Swiss Accelerator Research and Technology collaboration CHART. We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb₃Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP037
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP039	Developments in the Experimental Interaction Regions of the High Energy LHC	532
	L. van Riesen-Haupt, J.L. Abelleira University of Oxford, Oxford, United Kingdom J.L. Abelleira, E. Cruz Alaniz JAI, Oxford, United Kingdom J. Barranco García, T. Pieloni, C. Tambasco EPFL, Lausanne, Switzerland M. Hofer, J. Keintzel, R. Tomás, F. Zimmermann CERN, Meyrin, Switzerland
	Funding: Work supported by the Swiss institute for Accelerator Research and Technology , CHART. The High Energy LHC (HE-LHC) aims to collide 13.5 TeV protons in two high luminosity experiments and two low luminosity experiments. In the following, the recent updates in the two high luminosity experimental interaction regions (EIR) of the HE-LHC will be illustrated. These EIR aim to focus the beams to a β^* of 0.45 m at the interaction point (IP) to achieve a lifetime integrated luminosity of 10 ab^-1. On top of the triplet optics designed to achieve this, it will present energy deposition driven separation dipole designs, optics solutions for the matching section and dispersion suppressors as well as studies involving the integration into the lattice options. In particular it will outline geometric considerations, spurious dispersion suppression as well as results from dynamic aperture studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP039
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB001	Low Emittance Tuning of FCC-ee	574
	T.K. Charles The University of Melbourne, Melbourne, Victoria, Australia S. Aumon, B.J. Holzer, F. Zimmermann CERN, Meyrin, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001
About •	paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPRB052	Gamma Factory at CERN: Design of a Proof-of-Principle Experiment	685
	Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann CERN, Meyrin, Switzerland S.E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay JAI, Egham, Surrey, United Kingdom A. Apyan ANSL, Yerevan, Armenia E.G. Bessonov LPI, Moscow, Russia A. Bosco, S.M. Gibson, L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom F. Castelli Università degli Studi di Milano, Milano, Italy F. Castelli, C. Curatolo, L. Serafini INFN-Milano, Milano, Italy K. Kroeger FSU Jena, Jena, Germany A. Martens LAL, Orsay, France V. Petrillo Universita’ degli Studi di Milano, Milano, Italy M. Sapinski, T. Stöhlker GSI, Darmstadt, Germany G. Weber IOQ, Jena, Germany Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052
About •	paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPRB076	Free Electron Laser Driven by a High-Energy High-Current Energy-Recovery Linac	1844
	F. Zimmermann CERN, Geneva, Switzerland H. Aksakal KMSIU, Onikisubat / Kahramanmaras, Turkey A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi, Turkey Z. Nergiz Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
	Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871. The proposed electron-hadron collider LHeC, based on an energy recovery linac, employs an electron beam of 20 mA current at an energy of tens of GeV. This electron beam could also be used to drive a free electron laser (FEL) operating at sub-Angstrom wavelengths. Here we demonstrate that such FEL would have the potential to provide orders of magnitude higher peak power, peak brilliance and average brilliance, than any other FEL, either existing or proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB076
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP041	Damping Bunch Oscillations Due to Off-Axis Injection	2422
	F. Zimmermann, O. Etisken, N. Mounet, A. Oeftiger, S. Ogur, Y. Papaphilippou, B. Salvant CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871. In the FCC-ee pre-injector complex, a slightly modified SPS can serve as pre-booster. The baseline design foresees injecting the low-emittance electron and positron bunches off-axis into the SPS, and deploying strong wigglers to greatly enhance the radiation damping at the injection energy. We here compare the damping of large injection oscillations by means of radiation damping with the effect of other possible damping mechanisms such as a fast bunch-by-bunch feedback system and/or head-tail damping via nonzero chromaticity. As a by-product, we investigate the transverse beam stability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP041
About •	paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPGW009	DEVELOPMENT OF THE ELECTRON BEAM PROBE FOR HADRON SYNCHROTRONS.	2480
	M. Droba, C. Hübinger, O. Meusel, H. Podlech, K.I. Thoma IAP, Frankfurt am Main, Germany O.R. Jones, M. Wendt, F. Zimmermann CERN, Meyrin, Switzerland
	Funding: BMBF 05P18RFRB2 Non-invasive diagnostics is essential to get important information about intense hadron beams, e.g. the transverse beam profile, which is indispensable in order to attain high brilliance and luminosity for upgrades on present machines and for future projects. Furthermore, it can be used to optimise parameter settings in environment of the running machine. An electron beam probe (EBP) is a beam diagnostics instrument which scans a low energy, low current electron beam through a hadron beam and obtains information from the detected response. The electrons are shot perpendicular through the hadron beam to be examined, which causes deflection in the beam potential of the intense hadron bunch, that needs to be detected and further analysed. We propose to build the EBP scanning apparatus for synchrotrons under ultra-high vacuum condition. The results of multi particle simulations evaluating limitations the expected measurement potential and limitations are presented. This work will be performed in collaboration with CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW009
About •	paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee

112

D. El Khechen, K. Oide, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW019

About •

paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP002

Linac and Damping Ring Designs for the FCC-ee

420

S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
I. Chaikovska, R. Chehab
LAL, Orsay, France
K. Furukawa, N. Iida, T. Kamitani, F. Miyahara, K. Oide
KEK, Ibaraki, Japan
E.V. Ozcan
Bogazici University, Bebek / Istanbul, Turkey
S.M. Polozov
MEPhI, Moscow, Russia
L. Rinolfi
ESI, Archamps, France
F. Yaman
IZTECH, Izmir, Turkey

We report the design of the pre-injector chain for the Future Circular e⁺ e⁻ Collider (FCC-ee) system. The electron beam from a low-emittance RF gun is accelerated by an S-band linac up to 6 GeV. A damping ring at 1.54 GeV is required for emittance cooling of the positron beam. The intermediate energy step from the exit of the S-band linac at 6 GeV to the 20 GeV injection energy of the top-up booster can be provided by the modified Super Proton Synchrotron (SPS), serving as a pre-booster ring (PBR). An alternative option to reach 20 GeV energy would be to extend the S-band linac with a C- or X-band linac. An overall cost optimisation will determine the choice of the final configuration. Beam loss and emittance dilution in the linac due to space charge effects, wakefields, and misalignment of accelerator components can be mitigated by RF phasing and orbit steering. Start-to-end simulations examine the beam transport through the linac up to either 6 GeV or 20 GeV. The results indicate large design margins. Simulations of the beam dynamics in the damping ring (DR) demonstrate a sufficiently large momentum acceptance. Effects of intrabeam scattering and electron cloud instability in the DR are also studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP002

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPMP003

Positron Source for FCC-ee

424

I. Chaikovska, R. Chehab, A. Faus-Golfe, Y. Han
LAL, Orsay, France
A. Apyan
ANSL, Yerevan, Armenia
Y. Enomoto, K. Furukawa, T. Kamitani, F. Miyahara, M. Satoh, Y. Seimiya, T. Suwada
KEK, Ibaraki, Japan
P.V. Martyshkin
BINP SB RAS, Novosibirsk, Russia
S. Ogur, K. Oide, Y. Papaphilippou, L. Rinolfi, P. Sievers, F. Zimmermann
CERN, Meyrin, Switzerland

The FCC-ee is a high-luminosity, high-precision circular collider to be constructed in a new 100 km tunnel in the Geneva area. The physics case is well established and the FCC-ee operation is foreseen at 91 GeV (Z-pole), 160 GeV (W pair production threshold), 240 GeV (Higgs resonance) and 365 GeV (t-tbar threshold). Due to the large 6D production emittance and important thermal load in the production target, the positron injector, in particular the positron source, is one of the key elements of the FCC-ee, requiring special attention. To ensure high reliability of the positron source, conventional and hybrid targets are currently under study. The final choice of the positron target will be made based on the estimated performances. In this framework, we present a preliminary design of the FCC-ee positron source, with detailed simulation studies of positron production, capture and primary acceleration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP003

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paper received ※ 03 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP023

Dynamic Aperture at Injection Energy for the HE-LHC

480

SUSPFO101

use link to see paper's listing under its alternate paper code

M. Hofer, M. Giovannozzi, J. Keintzel, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
L. van Riesen-Haupt
JAI, Oxford, United Kingdom

As part of the Future Circular Collider study, the High Energy LHC (HE-LHC) is a proposed hadron collider situated in the already existing LHC tunnel. It aims at achieving a center of mass energy of 27 TeV, almost doubling the design c.o.m. energy of the LHC. This increase in energy relies on the use of 16 T Nb₃Sn dipoles to be developed for the FCC-hh. The field quality of these dipoles is expected to have a big impact on the Dynamic Aperture (DA) at injection energy and subsequently tracking studies are conducted to evaluate the impact of magnetic field errors on the beam dynamics. In the following the results of these studies for the different injection energies considered for the HE-LHC are presented and a possible strategy for increasing the DA are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP023

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paper received ※ 06 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP026

HE-LHC Optics Design Options

492

SUSPFO103

use link to see paper's listing under its alternate paper code

J. Keintzel, M.P. Crouch, M. Hofer, T. Risselada, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
M. Hofer, J. Keintzel
TU Vienna, Wien, Austria
L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom
L. van Riesen-Haupt
JAI, Oxford, United Kingdom

The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP026

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paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPMP035

Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider

516

M.A. Valdivia García, F. Zimmermann
CERN, Meyrin, Switzerland

Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035

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paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPMP037

Updated High-Energy LHC Design

524

F. Zimmermann, D. Amorim, S.A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, J. Keintzel, R. Kersevan, V. Mertens, J. Molson, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann
CERN, Geneva, Switzerland
J.L. Abelleira, A. Abramov, E. Cruz Alaniz, H. Pikhartova, A. Seryi, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
A. Apyan
ANSL, Yerevan, Armenia
J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco
EPFL, Lausanne, Switzerland
F. Burkart
DESY, Hamburg, Germany
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
G. Guillermo Cantón
CINVESTAV, Mérida, Mexico
K. Ohmi, K. Oide, D. Zhou
KEK, Ibaraki, Japan

Funding: This work was supported in part by the European Commission under the HORIZON 2020 project ARIES no.730871, and by the Swiss Accelerator Research and Technology collaboration CHART.
We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb₃Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP037

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPMP039

Developments in the Experimental Interaction Regions of the High Energy LHC

532

L. van Riesen-Haupt, J.L. Abelleira
University of Oxford, Oxford, United Kingdom
J.L. Abelleira, E. Cruz Alaniz
JAI, Oxford, United Kingdom
J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland
M. Hofer, J. Keintzel, R. Tomás, F. Zimmermann
CERN, Meyrin, Switzerland

Funding: Work supported by the Swiss institute for Accelerator Research and Technology , CHART.
The High Energy LHC (HE-LHC) aims to collide 13.5 TeV protons in two high luminosity experiments and two low luminosity experiments. In the following, the recent updates in the two high luminosity experimental interaction regions (EIR) of the HE-LHC will be illustrated. These EIR aim to focus the beams to a β^* of 0.45 m at the interaction point (IP) to achieve a lifetime integrated luminosity of 10 ab^-1. On top of the triplet optics designed to achieve this, it will present energy deposition driven separation dipole designs, optics solutions for the matching section and dispersion suppressors as well as studies involving the integration into the lattice options. In particular it will outline geometric considerations, spurious dispersion suppression as well as results from dynamic aperture studies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP039

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB001

Low Emittance Tuning of FCC-ee

574

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
S. Aumon, B.J. Holzer, F. Zimmermann
CERN, Meyrin, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm^-2s^-1. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB001

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paper received ※ 09 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPRB052

Gamma Factory at CERN: Design of a Proof-of-Principle Experiment

685

Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann
CERN, Meyrin, Switzerland
S.E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay
JAI, Egham, Surrey, United Kingdom
A. Apyan
ANSL, Yerevan, Armenia
E.G. Bessonov
LPI, Moscow, Russia
A. Bosco, S.M. Gibson, L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
F. Castelli
Università degli Studi di Milano, Milano, Italy
F. Castelli, C. Curatolo, L. Serafini
INFN-Milano, Milano, Italy
K. Kroeger
FSU Jena, Jena, Germany
A. Martens
LAL, Orsay, France
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy
M. Sapinski, T. Stöhlker
GSI, Darmstadt, Germany
G. Weber
IOQ, Jena, Germany
Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052

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paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPRB076

Free Electron Laser Driven by a High-Energy High-Current Energy-Recovery Linac

1844

F. Zimmermann
CERN, Geneva, Switzerland
H. Aksakal
KMSIU, Onikisubat / Kahramanmaras, Turkey
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi, Turkey
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871.
The proposed electron-hadron collider LHeC, based on an energy recovery linac, employs an electron beam of 20 mA current at an energy of tens of GeV. This electron beam could also be used to drive a free electron laser (FEL) operating at sub-Angstrom wavelengths. Here we demonstrate that such FEL would have the potential to provide orders of magnitude higher peak power, peak brilliance and average brilliance, than any other FEL, either existing or proposed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB076

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paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP041

Damping Bunch Oscillations Due to Off-Axis Injection

2422

F. Zimmermann, O. Etisken, N. Mounet, A. Oeftiger, S. Ogur, Y. Papaphilippou, B. Salvant
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871.
In the FCC-ee pre-injector complex, a slightly modified SPS can serve as pre-booster. The baseline design foresees injecting the low-emittance electron and positron bunches off-axis into the SPS, and deploying strong wigglers to greatly enhance the radiation damping at the injection energy. We here compare the damping of large injection oscillations by means of radiation damping with the effect of other possible damping mechanisms such as a fast bunch-by-bunch feedback system and/or head-tail damping via nonzero chromaticity. As a by-product, we investigate the transverse beam stability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP041

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW009

DEVELOPMENT OF THE ELECTRON BEAM PROBE FOR HADRON SYNCHROTRONS.

2480

M. Droba, C. Hübinger, O. Meusel, H. Podlech, K.I. Thoma
IAP, Frankfurt am Main, Germany
O.R. Jones, M. Wendt, F. Zimmermann
CERN, Meyrin, Switzerland

Funding: BMBF 05P18RFRB2
Non-invasive diagnostics is essential to get important information about intense hadron beams, e.g. the transverse beam profile, which is indispensable in order to attain high brilliance and luminosity for upgrades on present machines and for future projects. Furthermore, it can be used to optimise parameter settings in environment of the running machine. An electron beam probe (EBP) is a beam diagnostics instrument which scans a low energy, low current electron beam through a hadron beam and obtains information from the detected response. The electrons are shot perpendicular through the hadron beam to be examined, which causes deflection in the beam potential of the intense hadron bunch, that needs to be detected and further analysed. We propose to build the EBP scanning apparatus for synchrotrons under ultra-high vacuum condition. The results of multi particle simulations evaluating limitations the expected measurement potential and limitations are presented. This work will be performed in collaboration with CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW009

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paper received ※ 11 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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