Self-Adjustment of Internal Radiation Field to Compensate for Linearly VaryingdSpacing in X-Ray Diffraction

It is now well known from studies of "anomalous transmission" that the energy flow through a perfect crystal during symmetric Laue (transmission) diffraction is along the diffracting planes. If the planes are then fanned out, as in elastic bending, the question arises as to whether or not the radiation pattern can adapt itself to the changing $d$ spacing so as to maintain diffraction conditions. If it does, the exit Bragg angle should differ from the entrance Bragg angle by an amount proportional to the bend. Experimental evidence is presented to show that this is indeed the case. Germanium crystals, judged to be perfect because of lack of etch pits, were used. Various anomalies in the transmitted intensities indicate that defects still exist.