Keyword: emittance
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MOYAA01 Several Topics on Beam Dynamics in FCC-ee sextupole, dynamic-aperture, quadrupole, alignment 18
 
  • K. Oide
    KEK, Ibaraki, Japan
  • S. Aumon, T.K. Charles, D. El Khechen, T. Tydecks
    CERN, Meyrin, Switzerland
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: Work supported by the European Commission under Capacities 7th Framework Programme project EuCARD–2, grant agreement 312453, and the Horizon 2020 Programme project CREMLIN, grant agreement 654166.
Several studies on the beam dynamics at FCC-ee: low emittance tuning, dynamic aperture, beam blowup with/without beam beam, will be introduced. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-MOYAA01  
About • paper received ※ 23 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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MOYBA01 Round Colliding Beams at Vepp-2000 with Extreme Tuneshifts luminosity, collider, positron, electron 34
 
  • D.B. Shwartz, V.V. Anashin, O.V. Belikov, D.E. Berkaev, K. Gorchakov, A.S. Kasaev, A.N. Kirpotin, I. Koop, A.A. Krasnov, G.Y. Kurkin, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, D.V. Rabusov, Yu. A. Rogovsky, A.M. Semenov, A.I. Senchenko, D.N. Shatilov, P.Yu. Shatunov, Y.M. Shatunov, O.S. Shubina, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov
    BINP SB RAS, Novosibirsk, Russia
  • I. Koop, E. Perevedentsev, Yu. A. Rogovsky, A.I. Senchenko, Y.M. Shatunov, D.B. Shwartz
    NSU, Novosibirsk, Russia
  
  VEPP-2000 is the only electron-positron collider operating with round beams that allow to enhance beam-beam limit. VEPP-2000 with SND and CMD-3 detectors carried out two successful data-taking runs after new BINP injection complex was commissioned. The 2016/2017 run was dedicated to high energy range (640-1000 MeV per beam) while the 2017/2018 run was focused at 275-600 MeV/beam energies. With sufficient positron production rate and upgraded full-energy booster the collider luminosity was limited by beam-beam effects, namely flip-flop effect. Thorough machine tuning together with new ideas introduced to suppress flip-flop allowed to achieve high beam-beam tuneshift and bunch-by-bunch luminosity values at specific beam energies. The achieved luminosity increased 2-5 times in a whole energy range in comparison to phase-1 operation (2010-2013).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-MOYBA01  
About • paper received ※ 11 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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MOYBA04 Report from ARIES Muon Collider Workshop in Padua collider, factory, positron, target 41
 
  • F. Zimmermann
    CERN, Meyrin, Switzerland
  • M. Zanetti
    INFN- Sez. di Padova, Padova, Italy
  
  Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES no.~730871.
Several novel concepts could help the muon collider become a reality. These concepts include parametric ionization cooling, low-emittance muon production by positron annihilation (LEMMA scheme), production of low-emittance muon or positron beams using the Gamma Factory concept, and strategies to upgrade large accelerator complexes, like the LHC or the FCC, into a highest-energy muon collider. The muon collider workshop organized by ARIES APEC at Padua in July 2018 gathered the international community in order to review the recent progress and to formulate a common R\&D strategy. Several important conclusions and recommendations were drawn. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-MOYBA04  
About • paper received ※ 13 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUOAB02 Low-emittance Tuning for Circular Colliders sextupole, quadrupole, coupling, alignment 57
 
  • T.K. Charles
    The University of Melbourne, Melbourne, Victoria, Australia
  • S. Aumon, B.J. Holzer, K. Oide, T. Tydecks, F. Zimmermann
    CERN, Geneva, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
  
  The 100 km FCC-ee e+/e− circular collider requires luminosities in the order of 1035 cm-2 s-1 and very low emittances of 0.27 nm·prad for the horizontal plane and 1 pm·prad in the vertical. In order to reach these requirements, extreme focusing of the beam is needed in the interaction regions, leading to a vertical beta function of 0.8 mm at the IP. These challenges make the FCC-ee design particularly susceptible to misalignment and field errors. This paper describes the tolerance of the machine to magnet alignment errors and the effectiveness of optics and orbit correction methods that were implemented in order to bring the vertical dispersion to acceptable values, which in turn limits the vertical emittance. Thousands of misalignment and error seeds were introduced in MADX simulations and a comprehensive correction strategy, which includes macros based upon Dispersion Free Steering (DFS), linear coupling correction based on Resonant Driving Terms (RDTs) and response matrices, was implemented. The results are summarized in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOAB02  
About • paper received ※ 11 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUOBB01 Optics Aberration at IP and Beam-beam Effects luminosity, coupling, MMI, optics 66
 
  • K. Ohmi, Y. Funakoshi, H. Koiso, A. Morita, Y. Ohnishi, D. Zhou
    KEK, Ibaraki, Japan
  • K. Hirosawa
    Sokendai, Ibaraki, Japan
  
  Collision in SuperKEKB phase II commissioning has started in April 2018. Luminosity was lower than the geomterical value even in very low bunch current. Linear x-y coupling at IP caused by skew of QCS was conjectured as error source. x-y coupling correction using skew corrector of QCS resulted in luminosity recover of 2 times. After the QCS skew correction, luminosity is still limited at relatively low bunch current. Nonlinear x-y coupling at IP is conjectured as a source of the luminosity limitation. We discuss effects of linear and nonlinear x-y coupling at IP on the beam-beam performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOBB01  
About • paper received ※ 25 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUOBB04 Different Optics within Large Energy Region at BEPCII luminosity, lattice, operation, feedback 79
 
  • C.H. Yu, Y. Bai, C.C. Du, Z. Duan, Y.Y. Guo, D. Ji, S.C. Jiang, Y. Jiao, Y.M. Peng, Q. Qin, Y.S. Sun, S.K. Tian, J.Q. Wang, N. Wang, X. Wang, Y. Wei, Wen. Wen, J. Wu, Xing. Xing, Xu. Xu, C. Zhang, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  
  BEPCII is designed at the beam energy of 1.89 GeV. According to the requirements of high energy physics, BEPCII has been operated in the energy region from 1.0 GeV to 2.3 GeV since 2009. The energy region is quite large so that it is very important to select optics for the optimized luminosity. Different optics within different energy region at BEPCII will be introduced in detail in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOBB04  
About • paper received ※ 23 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUYBA03 Beam-beam Blowup in the Presence of x-y Coupling Sources for FCC-ee coupling, lattice, sextupole, simulation 112
 
  • D. El Khechen, K. Oide, F. Zimmermann
    CERN, Geneva, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
  
  FCC-ee, the lepton version of the Future Circular Collider (FCC), is a 100 Km future machine under study to be built at CERN. It acquires two experiments with a highest beam energy of 182.5 GeV. FCC-ee aims to operate at four different energies, with different luminosities to fulfill physics requirements. Beam-beam effects at such a high energy/luminosity machine are very challenging and require a deep understanding, especially in the presence of x-y coupling sources. Beam-beam effects include the beamstrahlung process, which limits the beam lifetime at high energies, as well as dynamic effects at the Interaction point (IP) which include changes in the beta functions and emittances. In this report, we will define the beam-beam effects and their behaviours in the FCC-ee highest energy lattice after introducing x-y coupling in the ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA03  
About • paper received ※ 11 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB02 Low Emittance Beam Transport for e−/e+ LINAC linac, electron, positron, gun 126
 
  • Y. Seimiya, N. Iida, M. Kikuchi, T. Mori
    KEK, Ibaraki, Japan
  
  Design luminosity of SuperKEKB is 8 x 1035 cm-2s-1, which is 40 times higher than that of KEKB achieved. To achieve the design luminosity, the beam have to be transported to the SuperKEKB main ring with the high bunch charge (4 nC) and low emittance: 40/20 um for horizontal/vertical electron beam emittance and 100/15 um for positron beam emittance in Phase 3 final. In the LINAC and the beam transport line, the emittance growth is mainly induced by residual dispersion, beam phase space jitter, wakefield in acceleration structure, and radiation excitation. In the Phase 2 operation, we have evaluated and, if possible, corrected these effects on the emittance. Results of the emittance measurement is described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB02  
About • paper received ※ 19 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB03 Overall Injection Strategy for FCC-ee linac, booster, collider, wiggler 131
 
  • S. Ogur, F. Antoniou, T.K. Charles, B. Härer, B.J. Holzer, Y. Papaphilippou, L. Rinolfi, T. Tydecks, F. Zimmermann
    CERN, Geneva, Switzerland
  • M. Aiba
    PSI, Villigen PSI, 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
  • O. Etisken
    Ankara University, Faculty of Sciences, Ankara, Turkey
  • K. Furukawa, N. Iida, T. Kamitani, F. Miyahara
    KEK, Ibaraki, Japan
  • E.V. Ozcan
    Bogazici University, Bebek / Istanbul, Turkey
  • S.M. Polozov
    MEPhI, Moscow, Russia
  
  The Future Circular electron-positron Collider (FCC-ee) requires fast cycling injectors with very low extraction emittances to provide and maintain extreme luminosities at center of mass energy varying between 91.2-385 GeV in the collider. For this reason, the whole injector complex table is prepared by putting into consideration the minimum fill time from scratch, bootstrapping, transmission efficiency as well as store time of the beams in synchrotrons to approach equilibrium emittances. The current injector baseline contains 6 GeV S-band linac, a damping ring at 1.54 GeV, a prebooster to accelerate from 6 to 20 GeV, which is followed by 98-km top up booster accelerating up to final collision energies. Acceleration from 6 GeV to 20 GeV can be provided either by Super Proton Synchrotron (SPS) of CERN or a new synchrotron or C-Band linac, distinctively, which all options are retained. In this paper, the current status of the whole FCC-ee injector complex and injection strategies are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB03  
About • paper received ※ 20 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB04 Overall Design of the CEPC Injector LINAC linac, positron, electron, damping 139
 
  • J.R. Zhang, Y.L. Chi, J. Gao, X.P. Li, C. Meng, G. Pei, S. Pei, D. Wang, C.H. Yu
    IHEP, Beijing, People’s Republic of China
  
  The CEPC injector consists of linac and booster. To meet the requirement of the booster, the linac should provide 10 GeV electron and positron beam at a repetition frequency of 100 Hz. In this paper, the overall design of the linac has introduced. For the linac one-bunch-per-pulse is adopted and bunch charge should be larger than 3 nC in the design. A 1.1 GeV damping ring with 75.4 m circumference has adopted to reduce the transverse emittance of positron beam to suitably small value.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB04  
About • paper received ※ 26 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB06 Design and Beam Dynamics of the CEPC Booster booster, injection, collider, optics 146
 
  • D. Wang, X. Cui, J. Gao, D. Ji, Y.D. Liu, C. Meng, N. Wang, C.H. Yu, J.Y. Zhai, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  
  The CEPC booster needs to provide electron and positron beams to the collider at different energy with required injection speed. A 10 GeV linac is adopted as the injector for CDR. Then the beam energy is accelerated to specific energy according to three modes of CEPC collider ring (H, W and Z). The geometry of booster is designed carefully in order to share the same tunnel with collider. The design status of booster including parameters, optics and dynamic aperture is discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB06  
About • paper received ※ 26 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB07 Commissioning of Positron Damping Ring and the Beam Transport for SuperKEKB linac, positron, MMI, operation 152
 
  • N. Iida, Y. Funakoshi, H. Ikeda, T. Ishibashi, H. Kaji, T. Kamitani, M. Kikuchi, T. Kobayashi, H. Koiso, F. Miyahara, T. Mori, Y. Ohnishi, Y. Seimiya, H. Sugimoto, H. Sugimura, R. Ueki, Y. Yano, D. Zhou
    KEK, Ibaraki, Japan
  
  The Positron Damping Ring (DR) for SuperKEKB successfully started its operation in February 2018, and the commissioning was continued until the end of SuperKEKB Phase 2 in July without serious troubles. This paper describes achievements of the beam commissioning of injection and extraction lines (LTR and RTL) between the LINAC and DR. In the LTR commissioning, the positron beam with high emittance, wide energy spread, and high charge were transported and injected into the DR. In the RTL commissioning, special cares were necessary to preserve the low emittance. The observed emittance growth in the RTL was not a problem for Phase 2, but it should be resolved in the coming Phase 3. In this paper, brief results of the commissioning of the DR is also reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB07  
About • paper received ※ 20 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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WEXBA03 Beam Blowup due to Lattice Coupling/Dispersion with/without Beam-beam resonance, lattice, synchrotron, coupling 207
 
  • K. Oide, D. El Khechen
    CERN, Meyrin, Switzerland
  
  Funding: Work supported by JSPS KAKENHI Grant Number 17K05475. Also supported by the European Commission under project EuCARD–2, grant agreement 312453, and under the Horizon 2020, grant agreement 654166.
A significant blowup of the vertical emittance is observed in particle tracking in lattices with random skew quadrupoles, even without beam-beam effects with the FCC-ee lattice at ttbar. A Vlasov model well explains the blowup, and agrees with the tracking. This effect will set an additional limit on the goal of tuning of the vertical emittance of the lattice of colliders, well below the value at the collision. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA03  
About • paper received ※ 25 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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