Robustness Test of a Silicon Strip Crystal for Crystal-Assisted Collimation Studies in the LHC

Over the past years, the UA9 experiment has successfully demonstrated the viability of enhancing the collimation efficiency of proton and ion beams in the SPS by means of bent crystals. An extension of UA9 to the LHC has been recently approved. The conditions imposed by the LHC operational environment, in particular the tremendous energy density of the beam, require a reliable understanding of the crystal integrity in view of potential accident scenarios such as an asynchronous beam dump. For this purpose, single pulse irradiation tests have been performed at the CERN-HiRadMat facility to examine the mechanical strength of a silicon strip crystal in case of direct beam impact. The tests were carried out using a 440 GeV proton beam of σ=0.5 mm transverse size. Individual pulse intensities reached up to 3×1013 protons, where a significant fraction is assumed to have impacted on the crystal. First visual inspections revealed no macroscopic damage to the crystal. Complementary post-irradiation tests are foreseen to assess microscopic lattice damage as well as the degradation of the channeling efficiency.