Observation of multiple volume reflection of ultrarelativistic protons by a sequence of several bent silicon crystals

The interactions of 400 GeV protons with different sequences of bent silicon crystals have been investigated at the H8 beam line of the CERN Super Proton Synchrotron. The multiple volume reflection of the proton beam has been studied in detail on a five-crystal reflector measuring an angular beam deflection ?=52.96±0.14?rad. The efficiency was found larger than 80% for an angular acceptance at the reflector entrance of 70?rad, with a maximal efficiency value of ?=0.90±0.01±0.03. © 2009 The American Physical Society.