Silicon crystal for channelling of negatively charged particles

Efficient channelling of negatively charged-particle beams in a bent crystal demands operation in axial mode, preferably along the < 111 > axis due to the strong confining potential generated along this direction. We propose a bent crystal suitable for steering negatively charged particle beams via axial channelling (AC) for operation at some gigaelectronvolt energy. The crystal is a quasi-mosaic crystal, relying on mechanical anisotropy of crystalline silicon. By use of high-resolution x-ray diffraction, we investigated the lattice bending of a crystal under the high-deformation regime. Anticlastic bending was found to weaken under a high deformation regime while anisotropic bending holds also under strong deformation. This circumstance envisages a versatile way to manage beams by AC.