Critical parameters of channeling

Basic methods for calculating critical channeling parameters that play a decisive role in the problem of dechanneling of ions are reviewed. The analytic expressions derived for the threshold energy of channeling, the critical transverse energy, and the closest approach distance between particles and atomic chains or planes forming the channels, as well as critical angles of axial and planar channeling, are valid in a wide range of particle energies. The dependence of critical parameters of channeling on the temperature of crystals is analyzed.