Author: Gross, K.     [Groß, K.]
Paper Title Page
TUPRI018 Transition Energy Crossing in the Future FAIR SIS-100 for Proton Operation 1591
 
  • S. Aumon, D. Ondreka, S. Sorge
    GSI, Darmstadt, Germany
  • K. Groß
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  The FAIR project foresees to deliver an intense single bunch beam with 2·1013 protons of 50ns duration to the experiments. Besides the original γt-shift scenario, an alternative RF proton cycle has been recently studied: the transition energy is crossed with possibly a gamma transition jump. The flexibility of the lattice allowing to change the value of γt, a transition crossing has been considered for two possible energies. This challenging scenario is limited by several constraints such as space charge, a small momentum acceptance and by the required RF manipulations aiming to produce the final single bunch beam in the future SIS-100. This paper focuses on how the high intensity beam would suffer of the mismatch in bunch length at transition and new sets of beam parameter are defined for the proton beam. The jump quadrupole system is also presented. The applicability of the foreseen longitudinal feedback system to cure quadrupolar oscillations is also discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI018  
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TUPRI073 Impact of Simplified Stationary Cavity Beam Loading on the Longitudinal Feedback System for SIS100 1736
 
  • K. Groß, H. Klingbeil, D.E.M. Lens
    TEMF, TU Darmstadt, Darmstadt, Germany
  • H. Klingbeil
    GSI, Darmstadt, Germany
  • D.E.M. Lens
    TU Darmstadt, RTR, Darmstadt, Germany
  
  Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) under the project 05P12RDRBF.
The main synchrotron SIS100 of the Facility for Antiproton and Ion Research (FAIR) will be equipped with a bunch-by-bunch feedback system to damp longitudinal beam oscillations. In the basic layout, one three-tap finite impulse response (FIR) filter will be used for each single bunch and oscillation mode. The detected oscillations are used to generate a correction voltage in dedicated broadband radio frequency (RF) cavities. The digital filter is completely described by two parameters, the feedback gain and the passband center frequency, which have to be defined depending on the longitudinal beam dynamics. In earlier works*, the performance of the closed loop control with such an FIR-filter was analyzed and compared to simulations and measurements with respect to the damping of coherent dipole and quadrupole modes, the first modes of oscillation. This contribution analyzes the influence of cavity beam loading on the closed loop performance and the choice of the feedback gain and passband center frequency to verify future high current operation at FAIR.
* H. Klingbeil et al., IEEE Trans. Nuc. Sci., Vol. 54, No. 6, 2007 and D. Lens et al., Phys. Rev. STAB 16, 032801, 2013. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI073  
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