The X-ray topographs of perfect and dislocated crystals were calculated by using the kinematic theory. The dislocation image on a X-ray topograph was found to be a circle, a

ridge or a trench; depending upon the type of dislocation and the diffraction condition. Its radius was comparable to that of the first Fresnel zone. The Fresnel model was applied to the X-ray topograph of solid He. The differing contrasts of sub-boundaries in the X-ray topographs of solid He were explained in terms of the contrast of the dislocation images.

Dislocation Image on X-Ray Topographs within Kinematic Theory. I.Iwasa: Physical Review B, 66[14] 144111 (11pp)