Author: Effinger, E.
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TUPMR051 New Spill Control for the Slow Extraction in the Multi-Cycling SPS 1371
  • V. Kain, K. Cornelis, E. Effinger
    CERN, Geneva, Switzerland
  The flux of particles slow extracted with the 1/3 integer resonance from the Super Proton Synchrotron at CERN was previously controlled with a servo-spill feedback system which acted on the horizontal tune such as to keep the spill rate as constant as possible during the whole extraction time. The current in two servo-quadrupoles was modulated as a function of the difference between the measured and the desired spill rate. With servo quadrupoles at a single location in the SPS ring and the SPS in multi-cycling mode, the trajectory of the slow extracted beam was seen to change from cycle to cycle depending on the current applied by the servo feedback. Hence this system was replaced by a feed-forward tune correction using the main SPS quadrupoles. In this way the spill control can now be guaranteed without changing the trajectory of the extracted beam. This paper presents the algorithm and implementation in the control system and summarizes the advantages of the new approach. The obtained spill characteristics will be discussed. The technique implemented for the additional reduction of the 50 Hz noise on the spill structure will also be briefly outlined.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR051  
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THPOR048 Beam Losses at CERNs PS and SPS Measured with Diamond Particle Detectors 3898
  • F. Burkart, W. Bartmann, B. Dehning, E. Effinger, M.A. Fraser, B. Goddard, V. Kain, O. Stein
    CERN, Geneva, Switzerland
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
  • O. Stein
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  Diamond particle detectors have been used in the LHC to measure fast particle losses with a nanosecond time resolution. In addition, these detectors were installed in the PS and the SPS. The detectors are mounted close to the extraction septum of the PS (transfer line to SPS) and the SPS (transfer lines TI2 and TI8 to LHC). Mainly, they monitor the losses occurring during the extraction process but the detectors are also able to measure turn-by-turn losses in the accelerators. In addition, detailed studies concerning losses due to ghost bunches were performed. This paper will describe the installed diamond detector setup, discuss the measurement results and possible loss mitigations.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR048  
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