Imaging of the energy flow in the three-beam case of x-ray diffraction

A new kind of topographic experiment is presented which makes it possible to depict the energy flow in the three-beam case of diffraction in Laue-Laue geometry. The crystal is illuminated by a highly collimated x-ray beam which is reduced in both cross-section dimensions (pinhole topography). These experiments allow the investigation of the dynamical interaction of the three diffracted waves in three-beam interference and also allow the predictions of the theory to be tested. The results are discussed with reference to the dispersion surface and are compared with the images taken in the arrangement for conventional slit limited section topography. (author)