Near 100% deflection efficiency in bent crystals using multiple volume reflection

Simulations of the trajectories of high-energy ions through several bent crystal layers show that ions can be reflected from each layer, resulting in a multiple volume reflection angle which is correspondingly increased in proportion to the number of layers. At certain configurations of a 20 layer structure we achieve a 100% deflection efficiency of high-energy ions through an angle which is 20 times greater than the critical angle. The range of entrance angles over which ions undergo volume reflection is 40 times greater than the critical angle. The use of several bent crystal layers to produce multiple volume reflection provides an alternative approach to beam steering which overcomes limitations of bent crystal channeling such as narrow angular acceptance and low deflection efficiency. This study shows that multiple volume reflection can be used for high efficiency collimation in high-energy colliders such as the LHC and ILC and for space and radiation shields based on bent crystals.