Crystals to assist the two-beam merging process in the UA9-apparatus

The UA9 Collaboration proposes to investigate a two-beam merging process aided by bent crystals in an improved version of an apparatus configured for the H8 beam line at the CERN-SPS North Area. The process involves generating two converging beams which combine inside a curved crystal. The resulting beam should include nearly all the incoming particles and to have a horizontal size almost equivalent to the sum of the converging beams. In practice, the combined beam is formed by horizontal stacking of the two original beams, with no active magnetic elements. Crystals shaped like a C, bent by two screws that compress the ends of the C, exhibit anticlastic bending with parabolic intensities, allowing easy production of the two converging beams and adjustment of their trajectory angles. The merging crystal is made of a short silicon strip to optimize channeling deflection and Multiple Coulomb Scattering. The merging process may be applicable, for instance, in the injector of a muon collider, as the increase in beam intensity occurs over a short distance with a minimal rise in emittance.