explain y x-rays, rather than other forms of EM radiation, r used 4 crystal diffraction studies?

Question

y not gamma rays or visible light instead of x-rays? [This refers to powder diffractometer & Miller Indices]

Answer 1

The wavelength of the X-rays is about the same as the spacing of the atoms in the crystal lattice; a fraction of a nm. Gamma rays are too short and visible light too long.