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New collimators are being produced at CERN in the framework of a largeparticle accelerator upgrade project to protect beam lines against strayparticles. Their movable jaws hold low density absorbers with tight geometricrequirements, while being able to withstand direct proton beam impacts. Suchevents induce considerable thermo-mechanical loads, leading to complexstructural responses, which make the numerical analysis challenging. Hence, anexperiment has been developed to validate the jaw design under representativeconditions and to acquire online results to enhance the numerical models. Twojaws have been impacted by high-intensity proton beams in a dedicated facilityat CERN and have recreated the worst possible scenario in future operation. Theanalysis of online results coupled to post-irradiation examinations havedemonstrated that the jaw response remains in the elastic domain. However, theyhave also highlighted how sensitive the jaw geometry is to its mounting supportinside the collimator. Proton beam impacts, as well as handling activities, mayalter the jaw flatness tolerance value by $\pm$ 70 ${\mu}$m, whereas theflatness tolerance requirement is 200 ${\mu}$m. In spite of having validatedthe jaw design for this application, the study points out numerical limitationscaused by the difficulties in describing complex geometries and boundaryconditions with such unprecedented requirements.

Full Scale Proton Beam Impact Testing of new CERN Collimators and Validation of a Numerical Approach for Future Operation