Author: Bartmann, W.
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WEPOST011 Studies on Top-Up Injection into the FCC-ee Collider Ring 1699
SUSPMF006   use link to see paper's listing under its alternate paper code  
 
  • P.J. Hunchak, M.J. Boland
    CLS, Saskatoon, Saskatchewan, Canada
  • M. Aiba
    PSI, Villigen PSI, Switzerland
  • W. Bartmann, Y. Dutheil, M. Hofer, R.L. Ramjiawan, F. Zimmermann
    CERN, Meyrin, Switzerland
  • M.J. Boland
    University of Saskatchewan, Saskatoon, Canada
 
  In order to maximize the luminosity production time in the FCC-ee, top-up injection will be employed. The positron and electron beams will be accelerated to the collision energy in the booster ring before being injected with either a small transverse or longitudinal separation to the stored beam. Using this scheme essentially keeps the beam current constant and, apart from a brief period during the injection process, collision data can be continuously acquired. Two top-up injection schemes, each with on- and off-momentum sub-schemes, viable for FCC-ee have been identified in the past and are studied in further detail to find a suitable design for each of the four operation modes of the FCC-ee. In this paper, injection straight optics, initial injection tracking studies and the effect on the stored beam are presented. Additionally, a basic proxy error lattice is introduced as a first step to studying injection into an imperfect machine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST011  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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WEPOST026 Conceptual Design of the FCC-ee Beam Dumping System 1753
SUSPMF002   use link to see paper's listing under its alternate paper code  
 
  • A.M. Krainer, P. Andreu Muñoz, W. Bartmann, M. Calviani, Y. Dutheil, A. Lechner, F.-X. Nuiry, A. Perillo-Marcone
    CERN, Meyrin, Switzerland
  • R.L. Ramjiawan
    JAI, Oxford, United Kingdom
 
  The Future Circular electron-positron Collider (FCC-ee) will have stored beam energies of up to 20 MJ. This is a factor 100 higher than any current or past lepton collider. A safe and reliable disposal of the beam onto a beam dump block is therefore critical for operation. To ensure the survival of the dump core blocks, transversal dilution of the beam is necessary. To reduce the complexity of the system and guarantee high availability, an optimized, semi-passive beam dumping system has been designed. The main dump absorber design has been optimized following recent studies for high energy dump block materials for the LHC High Luminosity upgrade. First simulations regarding the radiation environment of the dumping system have been carried out, allowing the definition of preliminary constraints for the integration with respect to radiation sensitive equipment. The performance of the system has been evaluated using Monte-Carlo simulations as well as thermomechanical Finite-Element-Analysis to investigate potential material failure and assess safety margins. An experiment at the CERN HiRadMat facility has been carried out and preliminary results show good agreement with simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST026  
About • Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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WEPOPT063 The FCCee Pre-Injector Complex 2007
 
  • P. Craievich, B. Auchmann, S. Bettoni, H.-H. Braun, M. Duda, D. Hauenstein, E. Hohmann, R. Ischebeck, P.N. Juranič, J. Kosse, G.L. Orlandi, M. Pedrozzi, J.-Y. Raguin, S. Reiche, S.T. Sanfilippo, M. Schaer, N. Vallis, R. Zennaro
    PSI, Villigen PSI, Switzerland
  • F. Alharthi, I. Chaikovska, S. Ogur
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • W. Bartmann, M. Benedikt, M.I. Besana, M. Calviani, S. Döbert, Y. Dutheil, O. Etisken, J.L. Grenard, A. Grudiev, B. Humann, A. Latina, A. Lechner, K. Oide, A. Perillo-Marcone, H.W. Pommerenke, R.L. Ramjiawan, Y. Zhao, F. Zimmermann
    CERN, Meyrin, Switzerland
  • A. De Santis
    INFN/LNF, Frascati, Italy
  • Y. Enomoto, K. Furukawa, K. Oide
    KEK, Ibaraki, Japan
  • O. Etisken
    Kirikkale University, Kirikkale, Turkey
  • C. Milardi
    LNF-INFN, Frascati, Italy
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • N. Vallis
    EPFL, Lausanne, Switzerland
 
  The international FCC study group published in 2019 a Conceptual Design Report for an electron-positron collider with a centre-of-mass energy from 90 to 365 GeV with a beam currents of up to 1.4 A per beam. The high beam current of this collider create challenging requirements on the injection chain and all aspects of the linac need to be carefully reconsidered and revisited, including the injection time structure. The entire beam dynamics studies for the full linac, damping ring and transfer lines are major activities of the injector complex design. A key point is that any increase of positron production and capture efficiency reduces the cost and complexity of the driver linac, the heat and radiation load of the converter system, and increases the operational margin. In this paper we will give an overview of the status of the injector complex design and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. In this framework, furthermore, we also present the preliminary studies of the FCC-ee positron source highlighting the main requirements and constraints.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT063  
About • Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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WEPOTK025 Concepts and Considerations for FCC-ee Top-Up Injection Strategies 2106
 
  • R.L. Ramjiawan, W. Bartmann, Y. Dutheil, M. Hofer
    CERN, Meyrin, Switzerland
  • M. Aiba
    PSI, Villigen PSI, Switzerland
  • P.J. Hunchak
    University of Saskatchewan, Saskatoon, Canada
  • P.J. Hunchak
    CLS, Saskatoon, Saskatchewan, Canada
 
  The Future Circular electron-positron Collider (FCC-ee) is proposed to operate in four modes, with beam energies from 45.6 GeV (Z-pole) to 182.5 GeV (tt-bar production) and luminosities up to 4.6×1036 cm2s-1. At the highest energies the beam lifetime would be less than one hour, meaning that top-up injection will be crucial to maximise the integrated luminosity. Two top-up injection strategies are considered here: conventional injection, employing a closed orbit bump and septum, and multipole-kicker injection, with a pulsed multipole magnet and septum. On-axis and off-axis injections are considered for both. We present a comparison of these injection strategies taking into account aspects such as spatial constraints, machine protection, disturbance to the stored beam and injection efficiency. We overview potential kicker and septum technologies for each.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK025  
About • Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
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WEPOTK026 Commissioning of the ELENA Electrostatic Transfer Lines for the Antimatter Facility at CERN 2110
 
  • Y. Dutheil, W. Bartmann, C. Carli, M.A. Fraser, D. Gamba, L. Ponce
    CERN, Meyrin, Switzerland
 
  ELENA is a small synchrotron ring that decelerates antiprotons down to a kinetic energy of 100 keV. With an experimental complex capable of housing up to 9 different experiments operating simultaneously, the transfer line design needed to be highly flexible. The low energy of the beam transported allowed the exploitation of electrostatic devices instead of magnets, to simplify design, production and operation. This contribution presents the systematic characterisation of the beam optics at the different experimental handover locations during beam commissioning using H ions from an external source, as well as the performance of the lines in operation with antiprotons. Finally, the effect of stray fields created by the experimental setup will be presented and compared with the first measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK026  
About • Received ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022  
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THPOTK043 Mitigation of High Voltage Breakdown of the Beam Screen of a CERN SPS Injection Kicker Magnet 2868
 
  • M.J. Barnes, W. Bartmann, M. Díaz Zumel, L. Ducimetière, L.M.C. Feliciano, T. Kramer, V. Namora, T. Stadlbauer, D. Standen, P. Trubacova, F.M. Velotti, C. Zannini
    CERN, Meyrin, Switzerland
 
  The SPS injection kicker magnets (MKP) were developed in the 1970’s, before beam induced power deposition was considered an issue. These magnets are very lossy from a beam impedance perspective: this is expected to be an issue during SPS operation with the higher intensity beams needed for HL-LHC. A design, with serigraphy applied to an alumina carrier, has been developed to significantly reduce the broadband beam coupling impedance and hence mitigate the heating issues. During high voltage pulse testing there were electrical discharges associated with the serigraphy. Detailed mathematical models have been developed to aid in understanding the transiently induced voltages and to reduce the magnitude and duration of electric field. In this paper, we discuss the solutions implemented to mitigate the electrical discharges while maintaining an adequately low beam-coupling impedance. In addition, the results of high voltage tests are reported. The alumina substrate has a high secondary electron yield and thus electron-cloud could be an issue, with SPS beam, if mitigating measures were not taken: this paper also discusses the measures implemented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK043  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
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