A study of oscillations in the angular distribution of volume reflected ions from bent crystals

Periodic oscillations in the angular distribution of volume reflected MeV protons which are transmitted through thin, curved crystals are observed in simulations. Such periodic oscillations are present even when the lattice radius of curvature is less than the critical radius. Previous studies have predicted and observed only uniform volume reflection along the lattice curvature, and the conditions under which uniform or periodic reflection occurs are studied. Oscillations are also observed in the simulated nuclear encounter probability under similar conditions, and a similar origin is attributed. The observations are extended to higher energies to predict when similar oscillations in the volume reflected angular distribution and nuclear encounter probability may be present in present beam extraction and collimation experiments at GeV and TeV energies