Characterization and core renovation of beam stoppers for personnel safety

To minimize the risk of accident on personnel accessing the PS complex at CERN transfer lines are equipped with beam stoppers. They immediately shut the beam aperture whenever members of personnel enter an accelerator or test facility. Most of them consist of cores out of stainless steel designed for a proton beam-pulse energy at 9.0 kJ during the 70’s. Further data on the design history of the beam stoppers is scarce. With the current pulse energy at 35.0 kJ steel reaches its structural limits. Based on the current function of the core requirements on the structural and beam-interaction performance of beam stoppers for personnel safety are drawn. To meet those requirements a compact core compatible to all PS complex is developed, replacing five existing design types. The new core introduces high-density sliced materials which withstand upgraded beam-pulse energies up to 92.5 kJ.