Testing the Double-Crystal Setup for Physics Beyond Colliders Experiments in the UA9-SPS Experiment

The UA9 experiment is installed in the CERN SPS to study how coherent interaction in crystalline materials can be used to steer particles beams. Recently, new experiments requiring complex beam manipulations by means of crystals have been proposed in the framework of the Physics Beyond Colliders study group at CERN. In particular, it was proposed to use a first crystal to direct protons from the LHC beam halo on a target placed in the beam pipe and to use a second crystal to deflect the particles produced in the target (double-crystal setup), allowing to measure their polarization. The layout of the UA9 experiment in the CERN SPS has been modified to study the feasibility of the proposed scenario and its compatibility with the delicate environment of a superconducting collider. A first set of measurements was performed in 2017 proving that the protons deflected by the first crystal can be intercepted and successfully deflected by a second crystal. A further upgrade of the experiment in 2018 will allow measuring more precisely the combined efficiency of the two crystals and the beam-induced background