Author: Klingbeil, H.
Paper Title Page
MOPHA021 Bunch-by-Bunch Longitudinal RF Feedback for Beam Stabilization at FAIR 820
 
  • K. Groß, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • U. Hartel, H. Klingbeil, U. Laier, D.E.M. Lens, K.-P. Ningel, S. Schäfer, B. Zipfel
    GSI, Darmstadt, Germany
  
  Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) under the project 05P12RDRBF.
To damp undesired longitudinal oscillations of bunched beams, the main synchrotron SIS100 of FAIR (Facility for Antiproton and Ion Research) will be equipped with a bunch-by-bunch feedback system. This helps to stabilize the beam, to keep longitudinal emittance blow-up low and to minimize beam losses. The proposed LLRF (low level radio frequency) topology of the closed loop feedback system is described. In some aspects, it is similar to the beam phase control system* developed at GSI Helmholtzzentrum für Schwerionenforschung GmbH. The differences and challenges are pointed out, which are mainly the bunch-by-bunch signal processing followed by the generation of a correction voltage in dedicated feedback cavities. The adapted topology was verified at SIS18 during beam time in 2014 using LLRF prototype subsystems and the two existing ferrite-loaded acceleration cavities. The experimental setup to damp coherent longitudinal dipole oscillations is presented and evaluated with focus on the realized modifications, including ongoing and pending investigations. Finally, the current status of the longitudinal feedback system for FAIR is summarized.
* Klingbeil et al., IEEE Trans. Nuc. Sci., Vol. 54, No. 6, 2007. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA021  
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WEPMA018 Status of the Ring RF Systems for FAIR 2789
 
  • M. Frey, R. Balß, C. Christoph, O. Disser, G. Fleischmann, U. Hartel, P. Hülsmann, S. Jatta, A. Klaus, H. Klingbeil, H.G. König, U. Laier, D.E.M. Lens, D. Mondry, K.-P. Ningel, H. Richter, S. Schäfer, C. Thielmann, T. Winnefeld, B. Zipfel
    GSI, Darmstadt, Germany
  • K. Groß, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  For the FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100 and the storage ring CR (Collector Ring), different RF cavity systems are currently being realized. In addition to the standard RF bucket generation and acceleration, these ring RF systems also allow more complex beam manipulations such as barrier bucket operation or bunch rotation in phase space. Depending on their purpose, the cavities are either loaded with ferrite material or with MA (Magnetic Alloy) ring cores. Independent of the type of cavity, a complete cavity system consists of the cavity itself, a tetrode-based power amplifier, a solid-state pre-amplifier, a supply unit including PLC (Programmable Logic Control), and an RF control system (so-called LLRF, low level RF system). In this contribution, the different systems are described, and their current status is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA018  
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