Characterisation of the bent silicon crystals and study of the inelastic nuclear interactions of 180 GeV/c pions in bent crystals at the UA9 experiment

Application of the bent crystals for particle beam collimation was proposed as an alternative way for the Large Hadron Collider collimation system. A first step towards the studies for LHC application is a characterization of bent crystals properties with a particle beam. It is essential for an understanding of the behavior of crystals used as collimators and in order to investigate their physical features for different future applications in the beam steering context. A deflection efficiency of about 60% was observed for 180 GeV/c pions due to planar channeling in the bent silicon crystal. In addition, a study of the probability of inelastic nuclear interactions (INI) of 180 GeV/c pion beam with silicon strip has been performed. The experimental data show that the probability of INI decreases in the region of channeling ($\sim 45\%$), while for the quasi-channeling orientation INI probability is higher ($\sim 102\%$), in comparison to the amorphous orientation.