The synchrotron SIS18 at GSI uses resonant extraction for slow beam extraction. Recently it was discovered that about 50% of the anode wires of the electrostatic extraction septum were broken during beam operation. In this paper, we present the analysis of the possible loss scenario that led to the anode wire damage and suggest machine protection measures to prevent future damage. The investigations revealed the importance of having access to stored data representing machine parameter settings and their changes as well as signals from devices and beam instrumentation to be able to analyse the events leading to losses. Relevant signals include beam current, beam loss monitor signals, and vacuum pressure. Systems for logging and archiving such data are under development for FAIR, but are not yet routinely available.

The synchrotron SIS100 at FAIR, currently under construction in Darmstadt, Germany, will deliver slow extracted proton and ion beams up to 100 Tm employing resonant extraction. Its compact super-ferric dipole and quadrupole magnets allow fast ramping of magnetic field up to 4 T/s and 57 (T/m)/s, respectively. Recently, field errors has been measured for the dipole magnets and the first batch of quadrupole magnets. Higher order multipoles may interfere with resonant extraction, changing the geometry of the separatrix and conditions for resonant particles. The latter are affected most during their last turns and in the extraction channel owing to their large amplitudes, which amplify the effect of higher order multipoles. SIS100 comprises a set of corrector magnets up to octupole order, which can be used to compensate the impact of magnetic field errors. In this contribution, we report on the status of the slow extraction simulation studies including field errors. Furthermore, we present alternative working points for slow extraction, which are necessary to avoid the transition energy for some of beams required by the FAIR experiments.