Author: Rumolo, G.
Paper Title Page
MOA1PL02 Beam Dynamics Challenges for the LHC and Injector Upgrades 8
 
  • G. Rumolo
    CERN, Geneva, Switzerland
 
  The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will rely on significantly higher bunch current and brightness to meet the future yearly integrated luminosity target. The implications are twofold. On one side, all the accelerators of the LHC injection chain will have to be upgraded to produce the desired beam parameters. For this purpose, the LHC Injectors Upgrade (LIU) program has been established to implement all the needed modifications for meeting the required beam specifications. These upgrades will lead to the lifting of the main intensity and brightness limitations in the injectors, linked to beam instabilities driven by impedance or electron cloud (e-cloud), and space charge. On the other side, the LHC will have to be able to swallow the new beam parameters. This will mainly require control of impedance driven instabilities and beam-beam effects, and e-cloud mitigation. In this paper, we will focus on proton beams by describing the identified performance limitations of the LHC and its injectors, as well as the actions envisioned to overcome them.  
slides icon Slides MOA1PL02 [13.138 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL02  
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WEA2WA01 High Intensity Effects of Fixed Target Beams in the CERN Injector Complex 237
 
  • E. Koukovini-Platia, H. Bartosik, M. Migliorati, G. Rumolo
    CERN, Geneva, Switzerland
  • M. Migliorati
    INFN-Roma1, Rome, Italy
  • M. Migliorati
    Sapienza University of Rome, Rome, Italy
 
  The current fixed target (FT) experiments at CERN are a complementary approach to the Large Hadron Collider (LHC) and play a crucial role in the investigation of fundamental questions in particle physics. Within the scope of the LHC Injectors Upgrade (LIU), aiming to improve the LHC beam production, the injector complex will be significantly upgraded during the second Long Shutdown (LS2). All non-LHC beams are expected to benefit from these upgrades. In this paper, we focus on the studies of the transverse instability in the Proton Synchrotron (PS), currently limiting the intensity of Time-Of-Flight (ToF) type beams, as well as the prediction of the impact of envisaged hardware modifications. A first discussion on the effect of space charge on the observed instability is also being presented.  
slides icon Slides WEA2WA01 [2.483 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA2WA01  
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WEP1WA01
Simulations of Electron-Ion Effects and Relevance to LHC Experience in 2017  
 
  • L. Mether
    EPFL, Lausanne, Switzerland
  • G. Iadarola, G. Rumolo
    CERN, Geneva, Switzerland
 
  Operation of the LHC in 2017 was severely affected by recurrent beam aborts triggered by beam losses in one of its arc cells. The losses were correlated with quickly developing transverse coherent oscillations, which in most cases caused the beam dumps due to particle losses in the cleaning insertions. The events are thought to have been caused by air that was frozen on the beam screen surface in the concerned location, and which through a complex sequence of events could give rise to a localized high gas density. In this contribution we describe efforts towards modelling the observed coherent effects through the interaction of the beam with the induced pressure bump.  
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WEP2PO011 Studies of Transverse Instabilities in the CERN SPS 291
 
  • M.S. Beck, H. Bartosik, M. Carlà, K.S.B. Li, G. Rumolo, M. Schenk
    CERN, Geneva, Switzerland
  • U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
 
  In the framework of the LHC Injectors Upgrade (LIU), beams with about twice the intensity compared to the present values will have to be accelerated by the CERN Super Proton Synchrotron (SPS) and extracted towards the Large Hadron Collider (LHC). Machine studies with intensity higher than the nominal LHC beam have shown that coherent instabilities in both transverse planes may develop at injection energy, potentially becoming a limitation for the future high intensity operation. In particular, a transverse mode coupling instability is encountered in the vertical plane, the threshold of which can be sufficiently increased by changing the machine optics. In addition, a headtail instability of individual bunches is observed in the horizontal plane in multi-bunch operation, which requires stabilization by high chromaticity. The PyHEADTAIL code has been used to check if the present SPS impedance model reproduces the experimental observations. The instability growth rates have been studied for different machine optics configurations and different chromaticity settings. Other stabilizing mechanisms like tune spread from octupoles or the transverse damper have also been investigated.  
poster icon Poster WEP2PO011 [4.940 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO011  
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THA1WD04 High-Brightness Challenges for the Operation of the CERN Injector Complex 352
 
  • K. Hanke, S.C.P. Albright, R. Alemany-Fernández, H. Bartosik, E. Chapochnikova, H. Damerau, G.P. Di Giovanni, B. Goddard, A. Huschauer, V. Kain, A. Lasheen, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, F. Tecker
    CERN, Geneva, Switzerland
 
  CERN's LHC injectors are delivering high-brightness proton and ion beams for the Large Hadron Collider LHC. We review the present operation modes and beam performance, and highlight the limitations. We will then give an overview of the upgrade program that has been put in place to meet the demands of the LHC during the High-Luminosity LHC era.  
slides icon Slides THA1WD04 [4.746 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD04  
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