One more possibility of using bent crystals for beam extraction from accelerators

A bent Si crystal placed before the first septum-magnet of the available slow extraction scheme of the IHEP accelerator allowed one to extract, for physical experiments, additional up to 3 × 108 protons to be lost otherwise at the septum in nonresonant slow extraction mode. It is about 10–30% of a the beam intensity extracted towards channel no. 22 without a bent crystal. The effect is due to volume channeling. The use of an unbent crystal as an amorphous target results in a decrease of the extracted beam intensity.