PPT Slide
There are perfect crystals, and then there are mosaic crystals
- If the rays coming in are perfectly parallel, the whole block of the perfect crystal will diffract, but only those blocks of the mosaic crystal that are aligned with the beam will diffract.
- To get all of the mosaic crystal to diffract, one must:
- Use an x-ray beam with crossfire, or
- Rotate the crystal in the beam.