Why diffraction is useful? Electrons interacts 100-1000 times stronger with matter than X-rays more absorption (need thin samples) can detect weak reflections not observed with x-rays,eg. superlattice reflection ·Useful for Identify crystalline phase -Orient crystals Lattice constant,crystal structure,orientation relationship etc. Understanding image contrast,in both diffraction contrast and HREM 5Why diffraction is useful? • Electrons interacts 100-1000 times stronger with matter than X-rays – more absorption (need thin samples) – can detect weak reflections not observed with x-rays, eg. superlattice reflection • Useful for – Identify crystalline phase – Orient crystals – Lattice constant, crystal structure, orientation relationship etc. • Understanding image contrast, in both diffraction contrast and HREM 5