Author: Vega Cid, L.
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WEPMK001 Preliminary Design of a Cooling System for the LHC Injection Kicker Magnets 2624
SUSPL086   use link to see paper's listing under its alternate paper code  
 
  • L. Vega Cid, M.J. Barnes, L. Ducimetière, M.T. Moester, V. Vlachodimitropoulos, W.J.M. Weterings
    CERN, Geneva, Switzerland
  • A. Abánades
    ETSII UPM, Madrid, Spain
 
  The CERN Large Hadron Collider (LHC) is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams from the injector chain. Future operation for High Luminosity LHC (HL-LHC) with high intensity beams will cause heating of the ferrite yokes of the MKIs beyond their Curie temperature, preventing injection until the yokes cool down. Beam coupling impedance studies show that it is possible to move a substantial portion of the beam induced power deposition from the upstream ferrite yokes, which are the yokes with the highest power deposition, to ferrite rings located at the upstream end of the magnet. Thermal predictions show that this power redistribution, combined with the installation of a cooling system around the rings, will maintain the temperatures of all the yokes and ferrite rings below their Curie point. Since the rings are not pulsed to high voltage, whereas the ferrite yokes are, the installation of a cooling system is feasible around the rings. The proposed design of the cooling system will be tested to ensure good performance before its installation on the MKIs. The details of the simulations and the design process are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK001  
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WEPMK002 Longitudinal Impedance Analysis of an Upgraded LHC Injection Kicker Magnet 2628
 
  • V. Vlachodimitropoulos, M.J. Barnes, L. Vega Cid, W.J.M. Weterings
    CERN, Geneva, Switzerland
 
  Prior to Long Shutdown 1 (LS1) one of the LHC injection kickers (MKIs) occasionally exhibited high temperatures leading to significant turnaround times. After a successful impedance mitigation campaign during LS1, the MKI ferrite yokes have remained below their Curie point and have not limited LHC's availability. However, for HL-LHC operation the MKI yokes are expected to exceed their Curie temperatures after long physics runs. To ensure uninterrupted future HL-LHC operation, a modified beam screen design, relocating some of the heat load to more easily cooled parts, and a suitable cooling system are under development as the current baseline for the HL-LHC upgrade of the MKIs. An upgraded beam screen providing such relocation has been designed, simulated and compared to the existing model. To validate simulations, two longitudinal beam coupling impedance measurement techniques have been used and the results are compared to predictions. The modified beam screen was implemented in an upgraded MKI installed in the LHC during the Year End Technical Stop (YETS) 2017/18.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK002  
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WEPMK003 An Upgraded LHC Injection Kicker Magnet 2632
 
  • M.J. Barnes, C. Bracco, G. Bregliozzi, A. Chmielinska, L. Ducimetière, B. Goddard, T. Kramer, H. Neupert, L. Vega Cid, V. Vlachodimitropoulos, W.J.M. Weterings, C. Yin Vallgren
    CERN, Geneva, Switzerland
  • A. Chmielinska
    EPFL, Lausanne, Switzerland
 
  Funding: Work supported by the HL-LHC project.
An upgrade of the LHC injection kickers is necessary for HL-LHC to avoid excessive beam induced heating of these magnets: the intensity of the HL-LHC beam will be twice that of LHC. In addition, in the event that it is necessary to exchange an injection kicker magnet, the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. Extensive studies have been carried out to identify practical solutions to these problems: these include redistributing a significant portion of the beam induced power deposition to ferrite parts of the kicker magnet which are not at pulsed high voltage and water cooling of these parts. Furthermore a surface coating, to mitigate dynamic vacuum activity, has been selected. The results of these studies, except for water cooling, have been implemented on an upgraded LHC injection kicker magnet: this magnet was installed in the LHC during the 2017-18 Year End Technical Stop. This paper presents the upgrades, including some test and measurement results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK003  
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