High efficiency beam deflection by planar channeling in bent silicon crystals

Experimental results on the deflection of a 450 GeV proton beam by means of (111) planar channeling in a bent silicon crystal are presented. The H8 microbeam in the CERN SPS North Area was tuned to be highly parallel in the horizontal plane, i.e. to a divergence smaller than the critical angle for planar channeling at this proton energy, and focused to less than 1 mm in the vertical plane. The Si crystal was bent to deflect the beam horizontally in a classical 3-point bender. Unprecedented deflection efficiencies of up to 50% have been observed. Since channeling of positive particles is a well-understood phenomenon over many orders of magnitude in particle energy, the present data can be extrapolated to the TeV range. This opens exciting possibilities for the application of bent crystals, e.g. as small and tunable beam splitters or as extraction devices, in the future multi-TeV proton accelerators