Author: Franchetti, G.
Paper Title Page
THYGBF3 Challenges of FAIR Phase 0 2947
 
  • M. Bai, A. Adonin, S. Appel, R. Bär, M.C. Bellachioma, U. Blell, C. Dimopoulou, G. Franchetti, O. Geithner, P. Gerhard, L. Groening, F. Herfurth, R. Hess, R. Hollinger, H.C. Hüther, H. Klingbeil, A. Krämer, S.A. Litvinov, F. Maimone, D. Ondreka, N. Pyka, S. Reimann, A. Reiter, M. Sapinski, B. Schlitt, G. Schreiber, M. Schwickert, D. Severin, R. Singh, P.J. Spiller, J. Stadlmann, M. Steck, R.J. Steinhagen, K. Tinschert, M. Vossberg, G. Walter, U. Weinrich
    GSI, Darmstadt, Germany
 
  After two-year's shutdown, the GSI accelerators plus the latest addition of storage ring CRYRING, will be back into operation in 2018 as the FAIR phase 0 with the goal to fulfill the needs of scientific community and the FAIR accelerators and detector development. Even though GSI has been well known for its operation of a variety of ion beams ranging from proton up to uranium for multi research areas such as nuclear physics, astrophysics, biophysics, material science, the upcoming beam time faces a number of challenges in re-commissioning its existing circular accelerators with brand new control system and upgrade of beam instrumentations, as well as in rising failures of dated components and systems. The cycling synchrotron SIS18 has been undergoing a set of upgrade measures for fulfilling future FAIR operation, among which many measures will also be commissioned during the upcoming beam time. This paper presents the highlights of the challenges such as re-establishing the high intensity heavy ion operation as well as parallel operation mode for serving multi users. The status of preparation including commissioning results will also be reported.  
slides icon Slides THYGBF3 [2.952 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF3  
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THPAK117 Space Charge Limitations for Bunch Compression in Synchrotrons 3518
SUSPF082   use link to see paper's listing under its alternate paper code  
 
  • Y.S. Yuan, O. Boine-Frankenheim
    TEMF, TU Darmstadt, Darmstadt, Germany
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt, Germany
 
  Bunch compression achieved via a fast bunch rotation in longitudinal phase space is a well-accepted scheme to generate short, intense ion bunches for various applications. During bunch compression, coherent beam instabilities and incoherent single particle resonances can occur because of increasing space charge, resulting in an important limitation for the bunch intensity. We present an analysis of the relevant space charge driven beam instability and resonance phenomena during bunch compression. A coupled longitudinal-transverse envelope approach is compared with Particle-In-Cell (PIC) simulations. Two distinct cases of crossing are discussed and applied to the GSI SIS18 heavy-ion synchrotron. It is shown that during bunch compression, the 90° condition of phase advance is associated with a fourth order single particle resonance and the 120° condition with the recently discovered dispersion-induced instability. The agreement between the envelope and PIC results indicates that the stop band is defined by the 120° dispersion instability, which should be avoided during bunch compression.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK117  
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