PS Complex beam stopper in Prévessin

The pictures show a new generation universal beam stopper that will be installed in different zones in the CERN Injectors Complex. Beam stoppers are classed as "Important Element for Safety of personnel". The Personnel Safety Access System operates them in order to protect personnel in the event of particle beam accidents and to protect personnel intervening in the accelerator tunnels from exposure to radiation produced by beam circulation or beam injection. The beam stopper consists of a particle absorbing core that remains out of the ultra-high vacuum particle beam line during normal operation of the accelerators. Before granting access to a facility or an accelerator, the beam stopper core is moved into the beam line in order to protect personnel entering areas downstream of the stopper. Analytical studies demonstrated that the beam stoppers currently installed in the PS complex would not be suitable for continuous beam impacts under the upgraded beam scenarios of post LS2 operation within the framework of the LHC Injector Upgrade (LIU) Project. The new beam stopper design will cope with the future beam conditions and offers the advantages of design standardisation, improved handling and mechanical interchangeability - along with compatibility with all beam-stopper positions in the PS. During Long Shutdown 2, 18 new generation universal beam stoppers will be installed to replace 13 old beam stoppers in the PS complex.