The PETRA IV project will have a storage ring with an ultra-low natural emittance of 20 pm rad [1]. For an off-axis injection scheme with working points at the difference resonance it is important to assure the vertical excursion arising due to transversal coupling such, that injection efficiency is not compromised. In this contribution we present simulations results of an off-axis injection near the coupling resonance, which provides equal equilibrium emittances. Advantages and disadvantages of such a scheme are discussed.

Radio Frequency Knock Out (RF KO) extraction is used to extract stored particle beams from synchrotrons through transverse excitation, delivering spills of particles for experiments and medical therapy. Minimizing the fluctuations of spill intensity is vital to prevent detector pile-up and interlocks while making most efficient use of the extracted beam. To improve the spill quality, different excitation signals with characteristic frequency spectra are explored. Results of experimental studies at the Heidelberg Ion Beam Therapy Center (HIT) are presented. These demonstrate the possible improvements by tuning multi-band spectra at different harmonics. Particle tracking simulations of the slow extraction process at HIT are used to understand how different excitation signals influence the spill quality.

Within the EU-funded activity IFAST, the task REX (Resonance Extraction Improvement) was launched in 2021 as WP 5.3. The IFAST-REX consortium comprises European hadron synchrotron facilities CERN and GSI, the hadron therapy centres CNAO, HIT, MedAustron, MIT and SEEIIST, as well as the companies Barthel HF-Technik and Bergoz Instrumentation. It deals with the crucial challenge of slow extraction in mitigating the current fluctuation on the time scale of typically 0.01 to 10 ms, primarily caused by magnet power supplier ripples. Higher frequency ripples due to the properties of beam excitation methods are also considered. IFAST-REX is organized into four modules: Two modules execute the realization of a high dynamic range low-frequency current transformer and tailored high power amplifiers for beam excitation. The other two modules focus on developing simulation tools for accurate long-term slow extraction and developing diagnostics related to extracted particle detection and analysis. This contribution summarizes the current status of the consortium efforts by indicating to selected results.