In Ewald sphere method to explain the diffraction condition, the following saying(s) is(are) correct.
A、the radius of Ewald sphere is in reverse proportion to wavelength of X-ray.
B、the length of diffracted beam vector is the same as the incident beam vector.
C、the reciprocal lattice does not change with X-ray.
D、the origin of reciprocal lattice coincides with the centre of Ewald sphere.
E、the surface of Ewald surface indicates the diffraction condition.