The beam wire scanners of the CERN Super Proton Synchrotron (SPS) experienced multiple failures of their carbon wires caused by the high-intensity beam during a very short period in April 2023. Different modifications of the existing instrument were therefore studied to reduce the beam-induced power without compromising its functionality nor negatively affecting the beam coupling impedance. Amongst these options were the implementation of ferrite absorbers, a change of the scanner mechanism and the installation of an RF coupler in the vacuum tank. In this paper, we introduce the electromagnetic simulation results for the installed ferrite loads and the RF coupler, as well as their impact on the on-axis beam impedance. The final improvement for the configuration to be installed during the end-of-year stop of the accelerator will be summarized.

During the last long shutdown of the accelerators at CERN (LS2), the main radio frequency system of the Proton Synchrotron Booster (PSB) was upgraded. A wideband system with Finemet magnetic alloy cavities driven by solid-state amplifiers replaced several different ferrite-loaded cavities. In measurements post-LS2, the longitudinal beam stability did not match predictions, which triggered a survey of the PSB impedance model. This started with the Finemet RF system, which are expected to be the dominant impedance contribution. Single stretched wire measurements were carried out with a 6-cell Finemet test cavity with different amplifier configurations. Measurement results and electromagnetic simulations are presented in this paper and compared to the previous impedance model. The electromagnetic characterization presented in this contribution will complement the beam-based impedance and low-level RF measurements as an input for the simulations of beam stability.