Author: Beck, M.S.
Paper Title Page
MOP2WA04 Recent Results from the Wideband Feedback System Tests at the SPS and Future Plans 38
 
  • K.S.B. Li, H. Bartosik, M.S. Beck, E.R. Bjørsvik, W. Höfle, G. Kotzian, T.E. Levens, M. Schenk
    CERN, Geneva, Switzerland
  • J.E. Dusatko, J.D. Fox, C.H. Rivetta
    SLAC, Menlo Park, California, USA
  • M. Schenk
    EPFL, Lausanne, Switzerland
  • O. Turgut
    Stanford University, Stanford, California, USA
 
  A high bandwidth transverse feedback demonstrator system has been devised within the LARP framework in collaboration with SLAC for the LHC Injectors Upgrade (LIU) Project. The initial system targeted the Super Proton Synchrotron (SPS) at CERN to combat TMCI and electron cloud instabilities induced for bunches with bunch lengths at the 100 MHz scale. It features a very fast digital signal processing system running at up to 4~GS/s and high bandwidth kickers with a frequency reach of ultimately beyond 1~GHz. In recent years, the system has gradually been extended and now includes two stripline kickers for a total power of 1~kW delivering correction signals at frequencies of currently more than 700~MHz. This talk will cover recent studies using this demonstrator system to overcome TMCI limitations in the SPS. We will conclude with future plans and also briefly mention potential applications and requirements for larger machines such as the LHC or the HL-LHC.  
slides icon Slides MOP2WA04 [19.091 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA04  
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TUP2WA05 Effect of the Extraction Kickers on the Beam Stability in the CERN SPS 189
 
  • A. Farricker, M.S. Beck, J. Repond, C. Vollinger
    CERN, Geneva, Switzerland
 
  Longitudinal beam instability in the CERN SPS is a major limitation in the ability to achieve the bunch intensities required for the goals of the High-Luminosity LHC project (HL-LHC). One of the major drivers in limiting the intensity of the machine is the broadband contribution to the beam-coupling impedance due to the kicker magnets. The extraction kickers (MKE) discussed in this paper are known to give a significant contribution to the overall longitudinal beam-coupling impedance. We present the results of bench measurements of the MKE's impedance to determine the accuracy of electromagnetic simulation models from which the impedance modelused for beam dynamics simulationsis constructed. In addition, we discuss the feasibility and implementation of beam measurements that can indicate the contribution of the MKE magnets to the longitudinal beam-coupling impedance of the SPS.  
slides icon Slides TUP2WA05 [2.698 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA05  
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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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