THYGBD —  MC1 Orals   (03-May-18   11:00—12:30)
Chair: W. Fischer, BNL, Upton, Long Island, New York, USA
Paper Title Page
THYGBD1 FCC: Colliders at the Energy Frontier 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 icon Slides THYGBD1 [12.508 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD1  
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THYGBD2 Results of UFO Dynamics Studies with Beam in the LHC 2914
 
  • B. Lindstrom, A. Apollonio, P. Bélanger, M. Dziadosz, A.A. Gorzawski, L. K. Grob, E.B. Holzer, A. Lechner, R. Schmidt, M. Valette, D. Valuch, D. Wollmann
    CERN, Geneva, Switzerland
 
  Micrometer sized particles entering the LHC beam (the so-called Unidentified Falling Objects or UFOs) are a known cause of localized beam losses since the beginning of high intensity beam operation, however the origin of these particles is not fully known. Their effect limits LHC availability by causing premature dumps due to excessive beam losses and occasionally even magnet quenches. This could become an important limitation for future accelerators such as the High Luminosity upgrade of the LHC (HL-LHC) and the Future Circular Collider (FCC). The dynamics of these UFOs was investigated in two dedicated experiments. In the first experiment, it was shown that the transverse movements of these particles can be studied by observing bunch-by-bunch losses from bunches with different horizontal and vertical emittances. In the second experiment, UFO-like events around the 16L2 interconnect in the LHC, which has seen intense UFO activity in 2017, were studied with the above method. This paper summarizes the results of both experiments.  
slides icon Slides THYGBD2 [1.361 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD2  
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THYGBD3 Beam-beam Studies for Super Proton-Proton Collider 2918
 
  • L.J. Wang, J.Y. Tang
    IHEP, Beijing, People's Republic of China
  • K. Ohmipresenter
    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 icon Slides THYGBD3 [1.379 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD3  
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THYGBD4 Landau Damping by Electron Lenses 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 icon Slides THYGBD4 [4.506 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD4  
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