what's the difference between Diffraction and Interference?

[jian]

I am a bit confused about these two concepts.

 

One example is the X-ray diffraction experiment.

I think the principle of X-ray diffraction is interference of X-rays, not the diffraction. why it is called diffraction?

[swansont]

Because diffraction is the source of the interference. You can do interference in many ways, but in e.g. a Michelson or Mach-Zehnder interferometer, you split the beam up and recombine it.

[WhataBohr]

equations to look at is the Helmholtz equation.. describes the wave equations