X-ray intensity patterns from finite perfect crystals

A theoretical study dealing with intensity interference patterns from the e xit surfaces of finite perfect t x l crystals has been undertaken using the Takagi-Taupin equations and the Riemann-Green technique. Numerical simulat ions have been performed for the 220 reflection in diamond allowing for dif ferent types of amplitude-modulated incoming plane waves, The effects cause d by limiting the waves by a slit system are also discussed. The results sh ow strong influence of the lateral crystal boundaries and are closely relat ed to the geometrical region structures formed by the characteristic lines associated with the equations. In the limit of a semi-infinite crystal, the Borrmann-Lehmann interference patterns are retrieved.