• A. Peters, E. Feldmeier, R. Steiner
  HIT, Heidelberg
• H. Eickhoff, T. Knapp, C.P. Welsch
  GSI, Darmstadt
• C. Schömers
  MPI-K, Heidelberg

The use of hadron beams delivered by normal conducting synchrotrons is highly attractive in various fundamental research applications as well as in the field of particle therapy. These applications require fast synchrotron operation modes with pulse-to-pulse energy variation and magnetic field slopes up to 10 T/s. The aims are to optimize the duty-cycle or to minimize treatment times for the patients as well as to provide extremely stable properties of the extracted beams, i.e. position and spill structure. Studies performed at the SIS18 synchrotron at GSI showed that not only the dipoles but the quadrupoles as well significantly contribute to the underlying time constants of the slowly extracted beam. An attempt has been made to measure the magnetic fields in synchrotron magnets with high precision and speed comparable to the current measurement with a DCCT. Additional magnetic field monitoring includes the retarding effects into the current control feedback loop neglecting the unfavourable dynamic effects from hysteresis and eddy currents. The presentation describes this controls approach, the results obtained at the HIT synchrotron and the SIS18 at GSI will be discussed.