Resonance Scattering of Fast Electrons in a Single Crystal
  It is shown that resonance scattering of fast ($pL > >pR > > 1$, $p$ is the particle momentum, $L$ is the longitudinal dimension of the potential, and $R$ is its transverse dimension) charged particles occurs in the extended potential. The data on small-angle scattering of fast electrons in the crystal are interpreted on the basis of the examined effect. 
Gennady V. Kovalev and Nikolay P. Kalashnikov
quant-ph