Observation of sub-GeV electrons mirrored by ultrathin crystalline Si

Detailed experimental studies are performed on the mirroring effect for 255-MeV electrons channeled through a 0.74-μm-thick Si crystal at the injector linac of the SAGA-LS facility. For the planar channeling alignment, deflection of the beam by 0.45 mrad is observed with 29% efficiency. The effect is explained by computer simulations as a sequence of trajectories of planar-channeled relativistic electrons in an attractive one-dimensional periodic potential of crystallographic planes. Possible applications as a beam splitter are proposed.