The divergent beam X-ray interference (DBI) method is commonly used to determine crystal systems, crystallographic orientation and lattice constants of single crystals and large indi-vidual grains and to get information on the real structure. Here back reflection divergent beam X-ray interference patterns (Pseudo-KOSSEL technique) were taken from polycrystalline specimens in the SEM and compared with corresponding lattice source interference (LSI) patterns (KOSSEL technique). A simulation program (for DBI) was developed allowing the calculation and indication of the complete reflex system as well as reflex sections. Reflex interruptions were obtained and could be explained by grain boundary effects. The influence of different important parameters such as the distance beween the target and the specimen, the target material, the orientation, the position, the shape and the size of the grains were discussed. Conclusions with respect to a local assignment of interruptions to grain boundaries are drawn so that now there is a possibility to localize the observed crystal defects.