A model for the interaction of high-energy particles in straight and   bent crystals implemented in Geant4
  A model for the simulation of orientational effects in straight and bent periodic atomic structures is presented. The continuum potential approximation has been adopted.The model allows the manipulation of particle trajectories by means of straight and bent crystals and the scaling of the cross sections of hadronic and electromagnetic processes for channeled particles. Based on such a model, an extension of the Geant4 toolkit has been developed. The code has been validated against data from channeling experiments carried out at CERN. 
E. Bagli, M. Asai, D. Brandt, A. Dotti, V. Guidi, D. H. Wright
physics.comp-ph cond-mat.other physics.acc-ph