Dynamics of electrons with energies up to several teraelectronvolts in oriented crystals

Stochastic aspects of the dynamics of electrons with energies from 150 GeV to several teraelectronvolts in silicon and germanium crystals oriented by the principal crystallographic directions along the beam axis are studied. The computations take into account the influence of emission of hard $\gamma$-quanta on the motion of electrons and also their multiple scattering from atoms of the target crystal. The lifetime of the electrons under channeling conditions are computed, and it is shown that this value (in the units of length) exactly coincides with the effective channeling length introduced earlier by Kumakhov [5].