Existence of quasi-stationary neutron and x-ray states near the surface of a deformed single crystal

The problem of x-ray or neutron multiply internally reflected inside a bent single crystal plate (Bragg geometry) is considered. It is found that such multiple reflections lead to the existence of quasi-stationary (QS) states. QS states are discrete and correspond to the resonance of motion of the tie point between the front surface and a 'turning place' inside a single crystal. (author)